Method for monitoring control signal of terminal in wireless communication system and terminal using the same

ABSTRACT

A method of monitoring a control signal in a wireless communication system, where the method is performed by a user equipment (UE) and includes: selecting at least one control resource set (CORESET) among a plurality of CORESETs based on an overlap between physical downlink control channel (PDCCH) monitoring occasions in the plurality of CORESETs; and monitoring a PDCCH only in the selected at least one CORESET, among the plurality of CORESETs. The method also includes: based on the at least one CORESET including a first CORESET, and based on a first reference signal of the first CORESET and a second reference signal of a second CORESET being associated with a same synchronization signal/physical broadcast channel block (SSB): monitoring the PDCCH in both the first CORESET and the second CORESET.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.16/922,435, filed on Jul. 7, 2020, which is a continuation of U.S.application Ser. No. 16/528,068, filed on Jul. 31, 2019, which pursuantto 35 U.S.C. § 119 (e) claims the benefit of an earlier filing date andright of priority to Korean Application No. 10-2018-0089551, filed onJul. 31, 2018, the contents of which are all hereby incorporated byreference herein in their entirety.

TECHNICAL FIELD

The present disclosure relates to wireless communication and, moreparticularly, to monitoring control signals of a terminal in a wirelesscommunication system.

BACKGROUND

As communication devices require more communication capacity, there is aneed for improved mobile broadband communication over existing radioaccess technology. Also, massive machine type communications (MTC),which provides various services by connecting many devices and objects,is one of the major issues to be considered in the next generationcommunication. In addition, communication system design consideringreliability and/or latency-sensitive service is being discussed. Theintroduction of next generation radio access technology consideringenhanced mobile broadband communication (eMBB), massive MTC (mMTC),ultrareliable and low latency communication (URLLC) is discussed. Thisnew technology may be called new radio access technology (new RAT or NR)in the present disclosure for convenience. NR is also referred to asfifth generation (5G) technology.

SUMMARY

Implementations are disclosed herein that enable monitoring controlsignals of a terminal in a wireless communication system.

One general aspect of the present disclosure includes a method ofmonitoring a control signal in a wireless communication system, themethod performed by a user equipment (UE) and including: selecting atleast one control resource set (CORESET) among a plurality of CORESETsbased on an overlap between physical downlink control channel (PDCCH)monitoring occasions in the plurality of CORESETs. The method alsoincludes monitoring a PDCCH only in the selected at least one CORESET,among the plurality of CORESETs, where based on the at least one CORESETincluding a first CORESET, and based on a first reference signal of thefirst CORESET and a second reference signal of a second CORESET beingassociated with a same synchronization signal/physical broadcast channelblock (SSB): monitoring the PDCCH in both the first CORESET and thesecond CORESET. Other embodiments of this aspect include correspondingcomputer systems, apparatus, and computer programs recorded on one ormore computer storage devices, each configured to perform the actions ofthe methods.

Implementations may include one or more of the following features. Themethod where, in selecting the at least one CORESET, a first priority ofa CORESET that includes a common search space (CSS) is higher than asecond priority of a CORESET that includes a UE-specific search space(USS). The method where selecting the at least one CORESET includes:based on the plurality of CORESETs including multiple CORESETs thatinclude a CSS: selecting the at least one CORESET to include a CORESET,among the multiple CORESETs that include the CSS, with a smallest index.The method where selecting the at least one CORESET includes: selecting,among the plurality of CORESETs, a CORESET that corresponds to a CSShaving a lowest index, from a cell that has a smallest cell index andthat contains the CSS. The method where the first CORESET and the secondCORESET are assumed by the UE to have same quasi co location (QCL)properties. The method where the QCL properties are related to a spatialreceive (RX) parameter. Implementations of the described techniques mayinclude hardware, a method or process, or computer software on acomputer-accessible medium.

Another general aspect of the present disclosure includes a userequipment (UE), the UE including: a transceiver. The user equipment alsoincludes at least one processor; and at least one computer memoryoperably connectable to the at least one processor and storinginstructions that, when executed by the at least one processor, performoperations including: selecting at least one control resource set(CORESET) among a plurality of CORESETs based on an overlap betweenphysical downlink control channel (PDCCH) monitoring occasions in theplurality of CORESETs. The operations also include monitoring a PDCCHonly in the selected at least one CORESET, among the plurality ofCORESETs, where based on the at least one CORESET including a firstCORESET, and based on a first reference signal of the first CORESET anda second reference signal of a second CORESET being associated with asame synchronization signal/physical broadcast channel block (SSB):monitoring the PDCCH in both the first CORESET and the second CORESET.Other embodiments of this aspect include corresponding computer systems,apparatus, and computer programs recorded on one or more computerstorage devices, each configured to perform the actions of the methods.

Implementations may include one or more of the following features. TheUE where, in selecting the at least one CORESET, a first priority of aCORESET that includes a common search space (CSS) is higher than asecond priority of a CORESET that includes a UE-specific search space(USS). The UE where selecting the at least one CORESET includes: basedon the plurality of CORESETs including multiple CORESETs that include aCSS: selecting the at least one CORESET to include a CORESET, among themultiple CORESETs that include the CSS, with a smallest index. The UEwhere selecting the at least one CORESET includes: selecting, among theplurality of CORESETs, a CORESET that corresponds to a CSS having alowest index, from a cell that has a smallest cell index and thatcontains the CSS. The UE where the first CORESET and the second CORESETare assumed by the UE to have same quasi co location (QCL) properties.The UE where the QCL properties are related to a spatial receive (RX)parameter. Implementations of the described techniques may includehardware, a method or process, or computer software on acomputer-accessible medium.

Another general aspect of the present disclosure includes at least oneprocessor that is configured to control a wireless communication deviceto perform operations including: selecting at least one control resourceset (CORESET) among a plurality of CORESETs based on an overlap betweenphysical downlink control channel (PDCCH) monitoring occasions in theplurality of CORESETs. The operations also include monitoring a PDCCHonly in the selected at least one CORESET, among the plurality ofCORESETs, where based on the at least one CORESET including a firstCORESET, and based on a first reference signal of the first CORESET anda second reference signal of a second CORESET being associated with asame synchronization signal/physical broadcast channel block (SSB):monitoring the PDCCH in both the first CORESET and the second CORESET.

Other embodiments of this aspect include corresponding computer systems,apparatus, and computer programs recorded on one or more computerstorage devices, each configured to perform the actions of the methods.

All or part of the features described throughout this disclosure can beimplemented as a computer program product including instructions thatare stored on one or more non-transitory machine-readable storage media,and that are executable on one or more processing devices. All or partof the features described throughout this disclosure can be implementedas an apparatus, method, or electronic system that can include one ormore processing devices and memory to store executable instructions toimplement the stated functions.

The details of one or more implementations of the subject matter of thisdisclosure are set forth in the accompanying drawings and thedescription below. Other features, aspects, and advantages of thesubject matter will become apparent from the description, the drawings,and the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows an example of wireless communication system to which thepresent disclosure may be applied;

FIG. 2 is a diagram showing an example of a wireless protocolarchitecture for a user plane;

FIG. 3 is a diagram showing an example of a wireless protocolarchitecture for a control plane;

FIG. 4 illustrates an example of a system structure of a next generationradio access network (NG-RAN) to which NR is applied;

FIG. 5 illustrates an example of a functional division between an NG-RANand a 5G core (5GC);

FIG. 6 illustrates an example of a frame structure that may be appliedin NR;

FIG. 7 illustrates an example of a control resource set (CORESET);

FIG. 8 is a diagram illustrating an example of a difference between arelated art control region and the CORESET in NR;

FIG. 9 illustrates an example of a frame structure for new radio accesstechnology;

FIG. 10 is a diagram illustrating an example of hybrid beamforming fromthe viewpoint of transceiver units (TXRUs) and physical antennas;

FIG. 11 illustrates an example of the beam sweeping operation for asynchronization signal and system information in a downlink (DL)transmission procedure;

FIG. 12 illustrates an example of a physical downlink control channel(PDCCH) monitoring technique of a user equipment (UE) according to oneimplementation of the present disclosure;

FIG. 13 illustrates an example of a case where two different CORESETsconfigured with different TCI states overlap each other in the timedomain;

FIG. 14 illustrates an example of an operation technique between agNodeB (gNB) and a UE according to one implementation of the presentdisclosure;

FIG. 15 illustrates an example of a technique for control channelmonitoring of a UE according to the present disclosure;

FIG. 16 illustrates an example of two reference signals associated withthe same synchronization signal block (SSB) described with reference toFIG. 15;

FIG. 17 is a block diagram showing an example of components of atransmitting device and a receiving device for implementing the presentdisclosure;

FIG. 18 illustrates an example of a signal processing module structurein the transmitting device;

FIG. 19 illustrates another example of the signal processing modulestructure in the transmitting device;

FIG. 20 illustrates an example of a wireless communication deviceaccording to an implementation example of the present disclosure;

FIG. 21 illustrates an example of a processor on the side of a terminal;and

FIG. 22 illustrates an example of a processor on the side of a basestation.

DETAILED DESCRIPTION

In some wireless communication systems, such as those compatible withLong Term Evolution (LTE) technology, a terminal monitors its controlchannels over the entire system bandwidth. On the other hand, in systemsthat are compatible with NR technology, a control channel of a userequipment (UE) may be monitored in a particular time/frequency resourcereferred to as a control resource set (CORESET) which is only a part ofthe system band. In such scenarios, a time point/occasion for monitoringthe control channel may be given. However, depending on situations, themonitoring occasions of the control channel may overlap among aplurality of CORESETs. In this case, problems may arise in how aterminal is to monitor the control channel.

Implementations of the present disclosure enable techniques formonitoring of control signals of a terminal in a wireless communicationsystem.

According to some implementations of the present disclosure, ifmonitoring times/occasions of a control channel overlap with each otheramong a plurality of CORESETs, then the control channel is monitoredonly in a specific CORESET which is selected according to priority. Inscenarios where a terminal does not monitor all of a plurality ofoverlapping CORESETs at a control channel monitoring time (occasion),the terminal may operate without problems, even in a communicationenvironment beyond capability of the terminal (e.g., in a system where anumber of allocated CORESETs is greater than the number of CORESETs thatthe terminal can monitor simultaneously). Also, in NR, beams may be usedfor transmission and reception. The parameters utilized for receivingthe beams may be referred to as spatial reception parameters. If themonitoring times/occasions of a control channel are overlapped among aplurality of CORESETs, then control channel monitoring efficiency may beincreased by ensuring that all CORESETs which exhibit the same spatialreception parameter properties perform control channel monitoring.

FIG. 1 shows an example of a wireless communication system to which thepresent disclosure may be applied. The wireless communication system maybe referred to as an Evolved-UMTS Terrestrial Radio Access Network(E-UTRAN) or a Long Term Evolution (LTE)/LTE-A system.

In this example, the E-UTRAN includes at least one base station (BS) 20which provides a control plane and a user plane to a user equipment (UE)10. The UE 10 may be fixed or mobile, and may be referred to as anotherterminology, such as a mobile station (MS), a user terminal (UT), asubscriber station (SS), a mobile terminal (MT), a wireless device, etc.The BS 20 is generally a fixed station that communicates with the UE 10and may be referred to as another terminology, such as an evolved node-B(eNB), a base transceiver system (BTS), an access point, etc.

The BSs 20 are interconnected by means of an X2 interface. The BSs 20are also connected by means of an S1 interface to an evolved packet core(EPC) 30, more specifically, to a mobility management entity (MME)through S1-MME and to a serving gateway (S-GW) through S1-U.

The EPC 30 includes an MME, an S-GW, and a packet data network-gateway(P-GW). The MME has access information of the UE or capabilityinformation of the UE, and such information is generally used formobility management of the UE. The S-GW is a gateway having an E-UTRANas an end point. The P-GW is a gateway having a PDN as an end point.

Layers of a radio interface protocol between the UE and the network canbe classified into a first layer (L1), a second layer (L2), and a thirdlayer (L3) based on the lower three layers of the open systeminterconnection (OSI) model that is well-known in the communicationsystem. Among them, a physical (PHY) layer belonging to the first layerprovides an information transfer service by using a physical channel,and a radio resource control (RRC) layer belonging to the third layerserves to control a radio resource between the UE and the network. Forthis, the RRC layer exchanges an RRC message between the UE and the BS.

FIG. 2 is a diagram showing an example of a wireless protocolarchitecture for a user plane. FIG. 3 is a diagram showing an example ofa wireless protocol architecture for a control plane. The user plane isa protocol stack for user data transmission. The control plane is aprotocol stack for control signal transmission.

Referring to FIGS. 2 and 3, a PHY layer provides an upper layer (higherlayer) with an information transfer service through a physical channel.The PHY layer is connected to a medium access control (MAC) layer whichis an upper layer of the PHY layer through a transport channel. Data istransferred between the MAC layer and the PHY layer through thetransport channel. The transport channel is classified according to howand with what characteristics data is transferred through a radiointerface.

Data is moved between different PHY layers (e.g., between the PHY layersof a transmitter and a receiver) through a physical channel. Thephysical channel may be modulated according to an Orthogonal FrequencyDivision Multiplexing (OFDM) scheme, and use both time resources andfrequency resources as radio resources.

The functions of the MAC layer include mapping between a logical channeland a transport channel and multiplexing and demultiplexing to atransport block that is provided through a physical channel on thetransport channel of a MAC Service Data Unit (SDU) that belongs to alogical channel. The MAC layer provides service to a Radio Link Control(RLC) layer through the logical channel.

The functions of the RLC layer include the concatenation, segmentation,and reassembly of an RLC SDU. In order to guarantee various types ofQuality of Service (QoS) required by a Radio Bearer (RB), the RLC layerprovides three types of operation mode: Transparent Mode (TM),Unacknowledged Mode (UM), and Acknowledged Mode (AM). AM RLC provideserror correction through an Automatic Repeat Request (ARQ).

The RRC layer is defined only on the control plane. The RRC layer isrelated to the configuration, reconfiguration, and release of radiobearers, and is responsible for control of logical channels, transportchannels, and PHY channels. An RB means a logical route that is providedby the first layer (PHY layer) and the second layers (MAC layer, the RLClayer, and the PDCP layer) in order to transfer data between UE and anetwork.

The function of a Packet Data Convergence Protocol (PDCP) layer on theuser plane includes the transfer of user data and header compression andciphering. The function of the PDCP layer on the user plane furtherincludes the transfer and encryption/integrity protection of controlplane data.

What an RB is configured means a process of defining the characteristicsof a wireless protocol layer and channels in order to provide specificservice and configuring each detailed parameter and operating technique.An RB can be divided into two types of a Signaling RB (SRB) and a DataRB (DRB). The SRB is used as a passage through which an RRC message istransmitted on the control plane, and the DRB is used as a passagethrough which user data is transmitted on the user plane.

If RRC connection is established between the RRC layer of UE and the RRClayer of an E-UTRAN, the UE is in the RRC connected state. If not, theUE is in the RRC idle state.

A downlink transport channel through which data is transmitted from anetwork to UE includes a broadcast channel (BCH) through which systeminformation is transmitted and a downlink shared channel (SCH) throughwhich user traffic or control messages are transmitted. Traffic or acontrol message for downlink multicast or broadcast service may betransmitted through the downlink SCH, or may be transmitted through anadditional downlink multicast channel (MCH). Meanwhile, an uplinktransport channel through which data is transmitted from UE to a networkincludes a random access channel (RACH) through which an initial controlmessage is transmitted and an uplink shared channel (SCH) through whichuser traffic or control messages are transmitted.

Logical channels that are placed over the transport channel and that aremapped to the transport channel include a broadcast control channel(BCCH), a paging control channel (PCCH), a common control channel(CCCH), a multicast control channel (MCCH), and a multicast trafficchannel (MTCH).

The physical channel includes several OFDM symbols in the time domainand several subcarriers in the frequency domain. One subframe includes aplurality of OFDM symbols in the time domain. An RB is a resourcesallocation unit, and includes a plurality of OFDM symbols and aplurality of subcarriers. Furthermore, each subframe may use specificsubcarriers of specific OFDM symbols (e.g., the first OFDM symbol) ofthe corresponding subframe for a physical downlink control channel(PDCCH), that is, an L1/L2 control channel. A Transmission Time Interval(TTI) is a unit time for subframe transmission.

Hereinafter, a new radio access technology (new RAT, NR) will bedescribed.

As more communication devices require more communication capacity, thereis a need for improved mobile broadband communication over existingradio access technology. Also, massive machine type communications(MTC), which provides various services by connecting many devices andobjects, is one of the major issues to be considered in the nextgeneration communication. In addition, communication system designconsidering reliability/latency sensitive service/UE is being discussed.The introduction of next generation radio access technology consideringenhanced mobile broadband communication (eMBB), massive MTC (mMTC),ultrareliable and low latency communication (URLLC) is discussed. Thisnew technology may be called new radio access technology (new RAT or NR)in the present disclosure for convenience.

FIG. 4 illustrates an example of a system structure of a next generationradio access network (NG-RAN) to which NR is applied.

Referring to FIG. 4, the NG-RAN may include a gNodeB (gNB) and/or aneNodeB (eNB) that provides user plane and control plane protocoltermination to a terminal. FIG. 4 illustrates the case of including onlygNBs. The gNB and the eNB are connected by an Xn interface. The gNB andthe eNB are connected to a 5G core network (5GC) via an NG interface.More specifically, the gNB and the eNB are connected to an access andmobility management function (AMF) via an NG-C interface and connectedto a user plane function (UPF) via an NG-U interface.

FIG. 5 illustrates an example of a functional division between an NG-RANand a 5G code (5GC).

Referring to FIG. 5, the gNB may provide functions such as an inter-cellradio resource management (Inter Cell RRM), radio bearer management (RBcontrol), connection mobility control, radio admission control,measurement configuration & provision, dynamic resource allocation, andthe like. The AMF may provide functions such as NAS security, idle statemobility handling, and so on. The UPF may provide functions such asmobility anchoring, PDU processing, and the like. The SMF may providefunctions such as UE IP address assignment, PDU session control, and soon.

FIG. 6 illustrates an example of a frame structure that may be appliedin NR.

Referring to FIG. 6, a frame may be composed of 10 milliseconds (ms) andinclude 10 subframes each composed of 1 ms.

One or a plurality of slots may be included in a subframe according tosubcarrier spacings.

The following Table 1 illustrates an example of a subcarrier spacingconfiguration μ.

TABLE 1 Δf = Cyclic μ 2^(μ) · 15 [kHz] prefix 0 15 Normal 1 30 Normal 260 Normal Extended 3 120 Normal 4 240 Normal

The following Table 2 illustrates an example of the number of slots in aframe (N^(frame,μ) _(slot)), the number of slots in a subframe(N^(subframe,μ) _(slot)), the number of symbols in a slot (N^(slot)_(symb)), and the like, according to subcarrier spacing configurationsμ.

TABLE 2 μ N_(symb) ^(slot) N_(slot) ^(frameμ) N_(slot) ^(subframeμ) 0 1410 1 1 14 20 2 2 14 40 4 3 14 80 8 4 14 160 16

In the example of FIG. 6, subcarrier spacing configurations of μ=0, 1, 2is illustrated.

A physical downlink control channel (PDCCH) may include one or morecontrol channel elements (CCEs) as illustrated in the example of Table3, below.

TABLE 3 Aggregation Number level of CCEs 1 1 2 2 4 4 8 8 16 16

That is, the PDCCH may be transmitted through a resource including 1, 2,4, 8, or 16 CCEs. Here, the CCE includes six resource element groups(REGs), and one REG includes one resource block in a frequency domainand one orthogonal frequency division multiplexing (OFDM) symbol in atime domain.

Meanwhile, in some wireless communication systems, a resource unitcalled a control resource set (CORESET) may be implemented. A terminalmay receive the PDCCH in the CORESET.

FIG. 7 illustrates an example of a CORESET.

Referring to FIG. 7, the CORESET includes N^(CORESET) _(RB) number ofresource blocks in the frequency domain, and N^(CORESET) _(symb) ∈{1, 2,3} number of symbols in the time domain. The parameters N^(CORESET)_(RB) and N^(CORESET) _(symb) may be provided by a base station, forexample via higher layer signaling. As illustrated in FIG. 7, aplurality of CCEs (or REGs) may be included in the CORESET.

The UE may attempt to detect a PDCCH in units of 1, 2, 4, 8, or 16 CCEsin the CORESET. One or a plurality of CCEs in which PDCCH detection maybe attempted may be referred to as PDCCH candidates.

In some implementations, a plurality of CORESETs may be configured forthe terminal.

FIG. 8 is a diagram illustrating an example of a difference between arelated art control region and the CORESET in NR.

Referring to FIG. 8, a control region 800 in the related art wirelesscommunication system (e.g., a system that is compatible with LTE/LTE-Atechnology) is configured over the entire system band used by a basestation (BS). All the terminals, excluding some (e.g., eMTC/NB-IoTterminal) supporting only a narrow band, must be able to receivewireless signals of the entire system band of the BS in order toproperly receive/decode control information transmitted by the BS.

On the other hand, in systems that are compatible with NR technology, aCORESET described above is implemented. In the example of FIG. 8,CORESETs 801, 802, and 803 are radio resources for control informationto be received by the terminal. Each of the CORESETs 801, 802, and 803may use only a portion, rather than the entirety, of the systembandwidth. The BS may allocate a CORESET to each UE, and the BS maytransmit control information through the allocated CORESET to the UE.For example, in FIG. 8, a first CORESET 801 may be allocated to UE 1, asecond CORESET 802 may be allocated to UE 2, and a third CORESET 803 maybe allocated to UE 3. In the NR, the terminal may receive controlinformation from the BS, without necessarily receiving the entire systemband.

The CORESET may include a UE-specific CORESET for transmittingUE-specific control information and a common CORESET for transmittingcontrol information common to all UEs.

In some scenarios, a system that is compatible with NR may require highreliability. In such situations, a target block error rate (BLER) fordownlink control information (DCI) transmitted through a downlinkcontrol channel (e.g., physical downlink control channel (PDCCH)) mayremarkably decrease compared to a BLER of other technologies. As anexample of a technique for achieving high reliability, content includedin DCI can be reduced and/or the amount of resources used for DCItransmission can be increased. Here, resources can include at least oneof resources in the time domain, resources in the frequency domain,resources in the code domain and resources in the spatial domain.

In NR, the following technologies/features can be applied.

<Self-Contained Subframe Structure>

FIG. 9 illustrates an example of a frame structure for new radio accesstechnology.

In NR, a structure in which a control channel and a data channel aretime-division-multiplexed within one TTI, as shown in FIG. 9, can beconsidered as a frame structure in order to minimize latency.

In FIG. 9, the hash-marked region represents a downlink control region,and a shaded region represents an uplink control region. The remainingregion may be used for downlink (DL) data transmission or uplink (UL)data transmission. This structure is characterized in that DLtransmission and UL transmission are sequentially performed within onesubframe and thus DL data can be transmitted and UL ACK/NACK can bereceived within the subframe. Consequently, a time required fromoccurrence of a data transmission error to data retransmission isreduced, thereby minimizing latency in final data transmission.

In this subframe structure in which both data and control aretime-division multiplexed (TDMed), a time gap may be implemented toallow for a base station and a terminal to switch from a transmissionmode to a reception mode or from the reception mode to the transmissionmode. To this end, some OFDM symbols in the self-contained subframestructure may be set to a guard period (GP) at a time when DL switchesto UL.

<Analog Beamforming #1>

In some scenarios of the present disclosure, wavelengths are shortenedto millimeter wave (mmW) lengths, enabling in a large number of antennaelements to be installed in an area. For example, a wavelength of 1 cmat 30 GHz may be implemented, resulting in a total of 100 antennaelements that can be installed in the form of a 2-dimensional array atan interval of 0.5 lambda (wavelength) in a panel of 5×5 cm.Accordingly, in the mmW wavelength regime, it is possible to increase abeamforming (BF) gain using a large number of antenna elements toincrease coverage or to improve throughput.

In this case, if a transceiver unit (TXRU) is provided to adjusttransmission power and phase per antenna element, independentbeamforming per frequency resource can be performed. However,installation of TXRUs for all of about 100 antenna elements decreaseseffectiveness in terms of cost. Accordingly, a technique of mapping alarge number of antenna elements to one TXRU and controlling a beamdirection using an analog phase shifter is considered. Such analogbeamforming can form only one beam direction in all bands and thuscannot provide frequency selective beamforming.

Hybrid beamforming (BF) having a number B of TXRUs which is smaller thanQ antenna elements can be considered as an intermediate form of digitalBF and analog BF. In this case, the number of directions of beams whichcan be simultaneously transmitted are limited to B although it dependson a technique of connecting the B TXRUs and the Q antenna elements.

<Analog Beamforming #2>

When a plurality of antennas is used in NR, hybrid beamforming which isa combination of digital beamforming and analog beamforming is emerging.Here, in analog beamforming (or RF beamforming) an RF end performsprecoding (or combining) and thus it is possible to achieve theperformance similar to digital beamforming while reducing the number ofRF chains and the number of D/A (or A/D) converters. For convenience,the hybrid beamforming structure may be represented by N TXRUs and Mphysical antennas. Then, the digital beamforming for the L data layersto be transmitted at the transmitting end may be represented by an N byL matrix, and the converted N digital signals are converted into analogsignals via TXRUs, and analog beamforming represented by an M by Nmatrix is applied.

FIG. 10 is a diagram illustrating an example of hybrid beamforming fromthe viewpoint of TXRUs and physical antennas.

In FIG. 10, the number of digital beams is L and the number of analogbeams is N. Further, in NR systems, by designing the base station tochange the analog beamforming in units of symbols, it is considered tosupport more efficient beamforming for a terminal located in a specificarea. Furthermore, when defining N TXRUs and M RF antennas as oneantenna panel in FIG. 7, it is considered to introduce a plurality ofantenna panels to which independent hybrid beamforming is applicable inthe NR system.

When a base station uses a plurality of analog beams as described above,analog beams suitable to receive signals may be different for terminalsand thus a beam sweeping operation of sweeping a plurality of analogbeams to be applied by a base station per symbol in a specific subframe(SF) for at least a synchronization signal, system information andpaging such that all terminals can have reception opportunities isconsidered.

FIG. 11 illustrates an example of the beam sweeping operation for asynchronization signal and system information in a downlink (DL)transmission procedure.

In FIG. 11, physical resources (or a physical channel) in which systeminformation of the NR system is transmitted in a broadcasting manner isreferred to as a physical broadcast channel (xPBCH). Here, analog beamsbelonging to different antenna panels can be simultaneously transmittedwithin one symbol, and a technique of introducing a beam referencesignal (BRS) which is a reference signal (RS) to which a single analogbeam (corresponding to a specific antenna panel) is applied in order tomeasure a channel per analog beam, as illustrated in FIG. 8, is underdiscussion. The BRS can be defined for a plurality of antenna ports, andeach antenna port of the BRS can correspond to a single analog beam.Here, all analog beams in an analog beam group are applied to thesynchronization signal or xPBCH and then the synchronization signal orxPBCH is transmitted such that an arbitrary terminal can successivelyreceive the synchronization signal or xPBCH.

In NR, a synchronization signal block (SSB), which includes asynchronization signal (SS) and a physical broadcast channel (PBCH), maybe composed of four OFDM symbols in the time domain, numbered in theascending order from 0 to 3 within the SSB; and a primarysynchronization signal (PSS), secondary synchronization signal (SSS),and PBCH associated with demodulation reference signal (DMRS) may bemapped to the symbols. Here, a synchronization signal block may betermed as an SS/PBCH block (or SSB for short).

In NR, a plurality of synchronization signal blocks (SSBs) may betransmitted at different times, respectively, and the SSB may be usedfor performing initial access (IA), serving cell measurement, and thelike. As such, it may be preferable to transmit the SSB first whentransmission time and resources of the SSB overlap with those of othersignals. To this end, the network may broadcast the transmission timeand resource information of the SSB or indicate them through UE-specificRRC signaling.

Further details of various implementations of the present disclosure aredescribed below. In what follows, an upper layer signal may refer to aRadio Resource Control (RRC) message, MAC message, or systeminformation.

In NR, beams may be used for transmission and reception. If receptionperformance of a current serving beam is degraded, a process ofsearching for a new beam through the so-called Beam Failure Recovery(BFR) may be performed.

Since the BFR process is not intended for declaring an error or failureof a link between the network and a UE, it may be assumed that aconnection to the current serving cell is retained even if the BFRprocess is performed. During the BFR process, measurement of differentbeams (which may be expressed in terms of CSI-RS port or SynchronizationSignal Block (SSB) index) configured by the network may be performed,and the best beam for the corresponding UE may be selected. The UE mayperform the BFR process in a way that it performs an RACH processassociated with a beam yielding a good measurement result.

The present disclosure describes a technique for configuring a CORESETand search space set required for performing the BFR process from theviewpoint of control channel processing and a candidate mappingtechnique for handling blind decoding (BD) and/or channel estimation(CE) complexity. The Transmission Configuration Indication (hereinafter,TCI) state in the present disclosure may be configured for each CORESETof a control channel and may be used as a parameter for determining areception (Rx) beam.

In some implementations, for each DL BWP of a serving cell, a UE may beconfigured for three or fewer CORESETs. Also, in some implementations, aUE may receive the following information for each CORESET:

1) CORESET index p (one of 0 to 11, where index of each CORESET may bedetermined uniquely among BWPs of one serving cell),

2) PDCCH DM-RS scrambling sequence initialization value,

3) Duration of a CORESET in the time domain (which may be given insymbol units),

4) Resource block set,

5) CCE-to-REG mapping parameter,

6) Antenna port quasi co-location representing quasi co-location (QCL)information of a DM-RS antenna port for receiving a PDCCH in eachCORESET (from a set of antenna port quasi co-locations provided by ahigher layer parameter called ‘TCI-State’),

7) Indication of presence of Transmission Configuration Indication (TCI)field for a specific DCI format transmitted by the PDCCH in the CORESET,and so on.

Here, ‘TCI-State’ parameter/information element is associated with a QCLtype (there may be QCL type A, B, C, and D; and for description of eachtype, refer to the example of Table 4, below) corresponding to one ortwo downlink reference signals.

TABLE 4 QCL Type Description QCL-TypeA Doppler shift, Doppler spread,average delay, delay spread QCL-TypeB Doppler shift, Doppler spreadQCL-TypeC Doppler shift, average delay QCL-TypeD Spatial Rx parameter

Each ‘TCI-State’ may include a parameter for configuring the quasico-location relationship between one or two downlink reference signalsand DM-RS port of the PDSCH/PDCCH.

The following Table 5 is an example of ‘TCI-State’ information element(IE).

TABLE 5 -- ASN1START -- TAG-TCI-STATE-START TCI-State ::= SEQUENCE { tci-StateId  TCI-StateId,  qcl-Type1   QCL-Info,  qcl-Type2   QCL-InfoOPTIONAL, -- Need R  ... } QCL-Info ::= SEQUENCE {  cell  ServCellIndexOPTIONAL, -- Need R  bwp-Id   BWP-Id  OPTIONAL, -- Cond CSI-RS-Indicated reference Signal  CHOICE {   csi-rs    NZP-CSI-RS-ResourceId,   SSB    SSB-Index  },  qcl-Type ENUMERATED {typeA, typeB, typeC, typeD}, ... } -- TAG-TCI-STATE-STOP -- ASN1STOP

Among the ‘TCI-State’ information elements, ‘bwp-Id’ informs of a DL BWPwhich a Reference Signal (RS) is located in. ‘cell’ informs of The UE'sserving cell in which the referenceSignal is configured. If the field isabsent, it applies to the serving cell in which the TCI-State isconfigured. The RS can be located on a serving cell other than theserving cell in which the TCI-State is configured only if the qcl-Typeis configured as typeC or typeD. ‘referenceSignal’ informs of Referencesignal with which quasi-collocation information is provided. ‘qcl-Type’may indicate at least one of QCL-Types of Table 4.

In some implementations, for a CORESET with index 0, the UE assumes thata DM-RS antenna port for PDCCH receptions in the CORESET is quasico-located with i) the one or more DL RS configured by a TCI state,where the TCI state is indicated by a MAC CE activation command for theCORESET or ii) a SS/PBCH block the UE identified during a most recentrandom access procedure not initiated by a PDCCH order that triggers anon-contention based random access procedure, if no MAC CE activationcommand indicating a TCI state for the CORESET is received after themost recent random access procedure.

For a CORESET other than a CORESET with index 0, if a UE is provided asingle TCI state for a CORESET, or if the UE receives a MAC CEactivation command for one of the provided TCI states for a CORESET, theUE assumes that the DM-RS antenna port associated with PDCCH receptionsin the CORESET is quasi co-located with the one or more DL RS configuredby the TCI state. For a CORESET with index 0, the UE expects thatQCL-TypeD of a CSI-RS in a TCI state indicated by a MAC CE activationcommand for the CORESET is provided by a SS/PBCH block.

If the UE receives the MAC CE activation command for one of the TCIstates, the UE may apply the activation command after 3 msec of a slotthat transmits HARQ-ACK information about the PDSCH providing theactivation command. An active BWP may be defined as an active BWP in aslot when the activation command is applied.

In one serving cell, the UE may receive 10 or fewer search space setsfrom each DL BWP configured for the UE. For each search space set, theUE may receive at least one of the following information:

1) Search space set index s (0≤s<40),

2) association between a CORESET P and the search space set s,

3) PDCCH monitoring periodicity and PDCCH monitoring offset (slot unit),

4) PDCCH monitoring pattern within a slot (for example, the patternindicates the first symbol of the CORESET within a slot for PDCCHmonitoring),

5) the number of slots in which the search space set s exists,

6) the number of PDCCH candidates for each CCE aggregation level,

7) information indicating whether the search space set s is a CSS or anUSS, or

8) DCI format that the UE has to monitor.

Next, further details are presented with regards to CORESETS for beamfailure recovery (BFR) and search space sets.

[CORESET for Beam Failure Recovery (BFR) and Search Space Set]

During the BFR process, when a UE performs a Random Access Channel(RACH) process by using a resource associated with a particular selectedbeam (e.g., a beam chosen as the best one), a CORESET and a search spacemay be used for receiving a signal from the network, such as a RandomAccess Response (RAR) message. Until a new CORESET and search spacereflecting additionally changed beam information are configured, the UEmay receive a UL grant or DL assignment through the BFR CORESET.

<Relationship Between BWP and ‘BFR CORESET and Search Space Set’>

In some implementations of NR systems, a maximum of 3 CORESETs and 10search space sets may be configured for each Bandwidth Part (BWP). Insuch scenarios, scheduling flexibility may be increased by making eachCORESET have different CORESET properties (for example, CCE-to-REGmapping (with or without interleaving), REG bundle size (for example, 2,3, 6 REGs), and wideband (WB)/narrow band (NB) reference signal) andmaking each search space set have a different monitoring occasion (inwhat follows, also referred to as monitoring times), differentaggregation level (AL), and/or different number of candidates. A UEmonitors a set of PDCCH candidates in one or more CORESETs on anactivated DL BWP of each activated serving cell for which PDCCHmonitoring is configured according to the corresponding search spacesets. Here, monitoring includes decoding each of the PDCCH candidatesaccording to the DCI format.

In the case of a BFR CORESET, (irrespective of scheduling flexibility ofthe aforementioned PDCCH transmission and reception) since it may benecessary for a process of searching for a new beam because ofdegradation of beam reception performance, it may be preferable not toapply the restriction corresponding to the maximum number of CORESETsper BWP (namely the restriction that allows 3 CORESETs for each BWP) tothe BFR CORESET. In other words, the UE may be configured with 3CORESETs excluding the BFR CORESET for each BWP and 10 search space setsexcluding the BFR search space set. When a normal CORESET is reused forthe BFR CORESET, if the normal CORESET is configured for a use ratherthan the BFR, the BFR CORESET may be included in the maximum number ofCORESETs for each BWP. This scheme may be applied the same for thesearch space set.

The BFR CORESET may be configured for each BWP or may be configured bythe initial BWP. When the BFR CORESET is configured for each BWP, thecorresponding configuration for each BWP may be applied, otherwise theBFR CORESET of the initial BWP may be monitored.

In addition, besides the following techniques, a previously configuredCORESET and/or CORESET that associates a search space set with the BFRand/or search space set may be reused. In this case, part of parametersof the CORESET configuration and/or search space set configuration maybe newly configured. For example, for the case of a parameter such asthe TCI state in the CORESET configuration, irrespective of a previousconfiguration, it may be assumed that in the BFR CORESET, the best beamis defined from the measurement of a UE or by the RACH process performedby the UE in the BFR process.

<Case where the BFR CORESET is Configured for Each BWP>

1) A BFR CORESET may always be configured for a BWP (namely, an activeBWP) for which a UE maintains transmission and reception to and from thecurrent network. This may be implemented through such a technique thatincludes information about the BFR CORESET within the BFR configuration.Also, a monitoring occasion of the BFR CORESET may be determined by aPRACH transmission time due to BFR. For example, the monitoring occasionof the BFR CORESET may be given by each slot within a Random AccessResponse (RAR) monitoring window after the PRACH transmission slot indexplus 4.

2) It may be preferable to consider/recognize that a connection to aserving cell is maintained even if the BFR process is under progress.Therefore, a UE may perform not only monitoring of the BFR CORESET butalso monitoring of DCI according to a previously configured CORESET andsearch space set configuration. For example, in the BFR CORESET, it maybe defined in a way to monitor only the PDCCH scrambled with C-RNTI. Inthis case, since there are times that the information allocated with aunique RNTI such as slot format indicator or slot format index (SFI),system information (SI), or paging is not transmitted to the UE, it maybe preferable to maintain monitoring of an existing CORESET. At thistime, a technique for configuring actual candidates by which a UEperforms monitoring will be described later.

<Case where the BFR CORESET is Configured for the Initial BWP>

1) The initial BWP may be basically configured with a CORESET configuredby the PBCH (CORESET #0) and CORESET configured for the RACH process(CORESET #1); and if the CORESET #1 is not configured, the CORESET #0may be reused for the CORESET #1.

2) When conventional DCI monitoring is performed, the UE may have toperform monitoring of different BWPs in the same slot to monitor theprevious DCI. In this case, the following techniques (options) may beconsidered.

Option 1) Monitoring of a BFR CORESET is considered to be a specialcase, and even when an active BWP does not coincide with the initialBWP, DCI monitoring for the BFR and monitoring of a previouslyconfigured DCI may all be performed.

Option 2) When a BWP performing DCI monitoring of BFR is different froma previous active BWP, DCI monitoring of the previous active BWP may notbe performed. Only when the BWP performing DCI monitoring of BFR is thesame as a previous active BWP, a technique for performing monitoring ofa previous DCI may be included.

3) When a BFR CORESET is configured for the initial BWP, the BFR CORESETmay be indicated by using the following technique (option).

Option 1) Reuse of CORESET #0 or CORESET #1

A BFR CORESET may be predefined or the network may configure a BFRCORESET to reuse a previously defined CORESET through higher layersignaling.

If the CORESET #0 is reused as a BFR CORESET, and BFR process isperformed based on the CSI-RS port, the network may signal therelationship between each CSI-RS port used in the BFR process and theSSB index associated with the CORESET #0. For example, a mappingrelationship between the CSI-RS port used in the BFR process and the SSBindex may be indicated through higher layer signaling.

Option 2) New CORESET for BFR

The network may indicate/provide a configuration for a BFR CORESETdefined within the initial BWP to each UE, and an indication/provisiontechnique may use a broadcast signal or UE-dedicated signal.

In the case of a BFR CORESET/SS, configuration may be optional.Therefore, if the BFR CORESET/SS is not configured within thecorresponding active BWP, or a BFR Contention Free Random Access (CFRA)resource is not configured, a UE may perform the following operation.

1) Beam recovery may be performed along a Contention Based Random Access(CBRA) resource. An RAR CORESET/SS associated with the correspondingCBRA resource may be assumed to be a BFR CORESET, in which a responsereception for a plurality of beams may be expected.

2) A response reception for a plurality of beams may be expected throughan RAR CORESET/SS associated with the CBRA resource.

3) A CFRA/CBRA/RAR CORESET/SS resource may be used by returning to theinitial DL/UL BWR Or, this option may be applied only to the case wherea BFR CORESET/SS or CFRA resource does not exist within thecorresponding active DL/UL BWR

[Blind Decoding and Channel Estimation Complexity on BFR Process]

In NR, monitoring of a plurality of CORESETs and search space sets maybe configured for the same slot. Therefore, the maximum number of blinddecoding (BD) and channel estimation that may be performed within oneslot may be defined by considering complexity of a UE, and those slotsthat exceed the corresponding maximum value may not perform monitoringfor part of the search space set/monitoring candidates. To performmonitoring of a BFR CORESET smoothly, a slot that performs monitoring ofthe BFR CORESET may configure a candidate that needs to be monitored asfollows (currently, for normal slots, BD and channel estimation for acommon search space (CSS) are performed first, and it is assumed thatthe limit due to the CSS is not exceeded. Afterwards, candidateselection (or mapping) at the search space set level is performed for aUE-specific search space (USS), and it is assumed that a lower searchspace index corresponds to higher priority for a plurality of USSs).

<Priority of BFR Search Space Set>

1) Monitoring of a BFR search space set may be designated as the highestpriority, i) Since serving beam configuration has to be performed firstin the BFR process, monitoring of candidates belonging to a search spaceset related to BFR has to be performed, ii) Therefore, a search spaceset related to BFR (for example, a response with respect to the PRACHtransmitted by a UE during the BFR process and a subsequent process) mayconfigure the highest priority irrespective of the type (for example,CSS/USS) of the corresponding BFR search space set, and it may beassumed that no candidate belonging to the corresponding search spaceset exceeds the limit.

2) Monitoring of a BFR search space set may be performed separately fromBD per slot and CCE limit. For BFR-related DCI, decoding may notnecessarily have to be completed within a slot that receives the DCI.Therefore, previously configured DCI monitoring may be performedcontinuously by considering BD per slot and CCE limit, and monitoring ofan SFR search space set may be performed independently. At this time, itmay be assumed that the BD and the number of CCEs configured by the BFRsearch space set do not exceed the limit.

<Assumption on CSSs>

As described above, for normal slots (in other words, slots that do notperform the BFR process), it may be assumed that configured commonsearch spaces do not exceed the maximum number of BDs and CCEs.

However, since the number of BD/CCEs for BFR monitoring is added when aBFR CORESET is monitored, there may be chances that the BD/CCE limit maybe exceeded when the BD/CCEs due to existing common search spaces aretaken into account. Therefore, the following assumption may be appliedfor a slot that monitors a BFR search space set. The following optionsmay be implemented separately or in the form of a combination thereof.The following options may be applied only to a common search space, butan USS according to a previous configuration may not be monitored duringthe BFR process. Or a candidate for monitoring may be chosen amongcommon search spaces according to the following options, and if there isroom for BD/CCE, the PDCCH may still be mapped to the search space setwith respect to the USS afterwards.

Option 1) It may be assumed that previously configured common searchspaces do not exceed the BD and CCE limit even in a BFR slot. This mayindicate that even if the network performs BD and channel estimation inthe BFR slot for a candidate related to BFR, the number of BDs and CCEsfor the common search spaces are set at least not to exceed a limitconfigured previously.

Option 2) If the number of BDs and CCEs in the common search spacesexceeds a limit configured previously due to the number of BDs and CCEsdue to a BFR search space set, search space set level drop may beapplied for the common search space(s). At this time, priority amongsearch space sets may be determined by search space 1 (for example, itis assumed that a low (high) search space index has high priority), DCIformat (for example, priority is defined for each DCI format), and soon.

For example, suppose a BD limit and a CCE limit defined within one slotare denoted by X_(slot) and Y_(slot), respectively; and the numbers ofBDs and CCEs configured for a BFR search space set are denoted byX_(BFR) and Y_(BFR). Then the numbers of BDs and CCEs allowed for thecommon search space(s) configured for the corresponding slot may beobtained by X_(CSS) (=X_(slot)−X_(BFR)), Y_(CSS) (=Y_(slot)−Y_(BFR)),respectively. At this time, among common search spaces configured forthe corresponding slot, if the numbers of BDs and CCEs of a commonsearch space set having the highest priority are smaller than X_(CSS)and Y_(CSS), blind decoding of the corresponding common search space maybe performed. Afterwards, X_(CSS) and Y_(CSS) values are updated, andthe corresponding process may be repeated for a common search spacehaving the second highest priority until one of the two limits isexceeded. BD may not be performed for a common search space that exceedsthe limit.

Candidate drop at a candidate level may also be included in the option2).

Option 3) If monitoring of a BFR search space set and one or more commonsearch space sets is configured in a specific slot; and the number ofBDs and/or CCEs due to the BFR search space set and the number of BDsand/or CCEs due to the common search space set(s) exceed thecorresponding limit, monitoring of the common search space may not beperformed.

Option 4) Monitoring of a BFR CORESET/SS may be included additionally toUE capability. In other words, a BFR CORESET/SS may assume that a UE isadditionally capable of performing channel estimation/BD beyond itsprevious capability as much as configured and may not consider channelestimation/BD limit. This indicates that capability with respect to aBFR CORESET and search space set may be defined separately, or thatBFR-related BD/channel estimation is assumed to be always performedindependently of BD/channel estimation for a normal DCI. A limit for BDand channel estimation may be applied to the remaining CORESETs/searchspace sets except for the BFR CORESET/search space set.

Option 5) In a slot where monitoring of a BFR CORESET is performed, itmay be predefined or indicated through higher layer signaling so thatonly a candidate corresponding to a specific RNTI among candidates of anexisting CORESET/search space set is monitored. For example, in a slotwhere monitoring of a BFR CORESET is performed, it may be configured sothat only a PDCCH candidate related to SFI from a previously configuredCORESET/search space set is monitored. In addition, if the BD/CCE limitis exceeded at the time of monitoring of an existing CORESET, monitoringof the existing CORESET may not be performed.

Option 6) In a slot where a BFR CORESET has to be monitored, it may bepredefined or indicated through higher layer signaling so thatmonitoring of other CORESETs except for the BFR CORESET is notperformed.

[Rx Beam Priority]

As described above, in NR, limits for the numbers of BDs and CCEs aredefined in terms of UE complexity, and if the corresponding limits areexceeded in a specific slot, monitoring of part of monitoring candidatesmay be skipped. A technique based on the operating scheme above may alsobe applied for an Rx beam used for specific time resources.

In some implementations of NR systems, monitoring of a plurality ofCORESETs may be performed in the same slot. In such implementations,scenarios may occur where the CORESETs may be overlapped with each otherin the time/frequency domain. Also, for each CORESET, a different QuasiCo-Location (QCL) assumption may be applied (namely, TCI state for aPDCCH may be set differently for each CORESET).

This implies that a plurality of CORESETs that have to receive differentRx beams at the same symbol may be included. However, a UE thatimplements only one RF panel may be capable of receiving only one Rxbeam from a specific time resource. In such implementations, the UE mayneed to select one Rx beam among the plurality of Rx beams. Receiving asignal by using a specific Rx beam may indicate that a spatial filter isapplied for receiving a specific signal from a viewpoint of UEimplementation. The aforementioned QCL assumption or TCI may be regardedas information related to the spatial filter application.

The present disclosure describes techniques for configuring one Rx beamamong a plurality of Rx beams, for example to address the scenariodescribed above. This operational scheme of the described technique maybe interpreted so that when a plurality of TCI states are set to thesame time domain resource, priorities of the corresponding TCI statesare configured, and a TCI state having the highest priority is appliedto the corresponding time domain resource. Also, this operational schememay also be interpreted as configuring the priorities of a plurality ofCORESETs that overlap in the time domain. As such, a particular Rx beammay be selected from among the plurality of Rx beams according to aselection technique that is based on such priorities.

If an Rx beam that a UE applied is determined (or TCI state isdetermined) by the following technique, network may perform transmissionin the CORESET associated with the corresponding Rx beam, or in the caseof a CORESET in which an improper Rx beam is used, reception performancemay be compensated for through coding rate or power boosting.

FIG. 12 illustrates an example of a PDCCH monitoring technique of a UEaccording to one implementation of the present disclosure.

Referring to FIG. 12, when PDCCH monitoring occasions overlap with eachother in a plurality of CORESETs, a UE selects a specific CORESET byincreasing the priority of a CORESET including a common search space(CSS) to be of higher priority than the priority of a CORESET includinga UE-specific search space (USS) S121.

The PDCCH is monitored in the selected specific CORESET (if there existsa CORESET that uses the same Rx beam as the selected CORESET (forexample, a CORESET having the same QCL properties (for example,QCL-typeD)), the corresponding CORESET is also included) S122.

In what follows, specific options (techniques) for selecting at leastone CORESET among the plurality of CORESETs are described. In whatfollows, for the convenience of descriptions, each option is describedseparately, but the following options may be used separately or in theform of combinations thereof.

Option 1) Measurement-Based Priority

A UE may configure an Rx beam at the corresponding time resource basedon measurement and report result. For example, one symbol in the timedomain may be mapped to three CORESETs in the frequency domain. In otherwords, three CORESETs may overlap in the time domain. In this case, whenQCL assumption is different for each CORESET, an Rx beam at thecorresponding symbol may be configured based on the best measurementresult among measurement results associated with the respectiveCORESETs. As one example, an Rx beam (or TCI state) associated with aCORESET having the highest RSRP value among the RSRP values measuredfrom the respective CORESETs (or RSRP value of a signal configured to aTCI state of each CORESET) may be applied to the corresponding symbol.In option 1, an Rx beam may be determined based on current measurementof a UE or determined based on a measurement result most recentlyreported. By reporting a value measured from each CORESET to a gNB, theUE may let the gNB (network) know the Rx beam to be selected by the UE.

Option 2) Priority Based on CORESET/Search Space Set Index

By assigning priority to a CORESET index or search space set index, Rxbeam to be applied to the corresponding resource may be determined. Forexample, a UE may configure an Rx beam based on a CORESET with thelowest (or highest) CORESET index or the TCI state of a CORESETassociated with the lowest search space set index.

Option 3) Message-Based Priority

A UE may configure an Rx beam based on the priority (for example, DCIformat, RNTI, and BFR) of a message that has to be monitored in eachCORESET. For example, an Rx beam of a CORESET monitoring DCI related toSFI, pre-emption, and so on may have higher priority than an Rx beam ofa CORESET monitoring non-fallback DCI.

As another example, an Rx beam of a CORESET monitoring informationneeded for maintaining communication of a UE such as RACH/SIupdate/paging may be configured to have higher priority.

As yet another example, the search space set type such as CSS/USS may beconsidered as an element for determining priority. More specifically,CSS may have higher priority than USS.

For the case of a CORESET related to beam failure recovery (or beammanagement), the highest priority may be assigned irrespective of theCORESET priority within a slot that has to perform monitoring.

For example, i) if a UE is configured for single cell operation or foroperation with carrier aggregation in the same frequency band, ii) ifthe UE monitors PDCCH candidates in overlapping PDCCH monitoringoccasions in multiple CORESETs that have same or different QCLproperties (for example, QCL-TypeD properties) on active DL BWP(s) ofone or more cells, the UE may monitor the PDCCH only in the CORESET onthe active DL BWP of a cell with the lowest index among one or morecells corresponding to the CSS set with the lowest index (if thereexists other CORESET having the same QCL properties (QCL-TypeDproperties) with the CORESET among the plurality of CORESETs, the otherCORESET is also included).

The lowest USS set index may be determined for all of the USS setshaving at least one PDCCH candidate among overlapped PDCCH monitoringoccasions.

For example, a UE that monitors a plurality of search spaces (alsoreferred to herein as search sets) associated with different CORESETsmay perform a single cell operation or a carrier aggregation operationwithin the same frequency band. In this case, if monitoring occasions ofthe search space (set) overlap in the time domain, and the search spacesare associated with different CORESETs having different QCL-TypeDproperties, the UE monitors the PDCCH in a CORESET corresponding to(including) a CSS (set) with the lowest index in an active DL BWP of aserving cell with the lowest serving cell index including the CSS. Atthis time, the UE may monitor a different CORESET with the sameQCL-TypeD properties as the QCL-TypeD properties of the given CORESET.For example, if two or more CORESETs include a CSS (set) respectively,then the UE may select a CORESET that includes a search space with thelowest index (or ID) among monitoring occasions in an active DL BWP of aserving cell with the lowest serving cell index. In such scenarios, theUE may monitor overlapping search spaces associated with CORESETs havingthe same QCL-TypeD properties as the CORESET.

If none of CORESETs includes a CSS, then a UE may select a CORESET thatincludes an USS with the lowest index (or ID) at a monitoring occasionin an active DL BWP of a serving cell with the lowest serving cellindex. In such scenarios, the UE may monitor overlapping search spacesassociated with the CORESETs having the same QCL-TypeD properties. Tothis end, when a CSI-RS originates from an SSB, the QCL-TypeD for theSSB and QCL-TypeD for the CSI-RS (or TRS) may be regarded as beingdifferent from each other.

In some implementations, an unselected search space may be regarded asdropping the whole search space (rather than puncturing that does notmonitor only the overlapping part of the search space).

Allocation of non-overlapping CCEs and PDCCH candidates for PDCCHmonitoring may be determined according to the entire search space setsassociated with a plurality of CORESETs on active DL BWP(s) of one ormore cells. The number of active TCI states may be determined from theplurality of CORESETs.

The UE may decode a PDSCH according to a (detected) PDCCH that includesDCI of the UE and may be configured with a list that includes up to MTCI-state configurations within a higher layer parameter called‘PDSCH-config’ for the decoding. And the M value may be dependent on theUE capability (for example, the maximum number of TCI states that may beactivated for each BWP).

Here, each TCI state may include parameters for configuring a quasico-location (QCL) relationship between (one or two) reference signalsand DM-RS ports of the PDSCH. The quasi co-location relationship may beconfigured by the higher layer parameter qcl-Type1 for a first downlinkreference signal (DL RS) and (if configured) the higher layer parameterqcl-Type2 for a second downlink reference signal (DL RS). QCL types maynot be the same for the two downlink reference signals. The quasico-location type corresponding to each downlink reference signal may begiven by a higher layer parameter qcl-Type (which is included in theQCL-Info) and may be one of QCL-TypeA, QCL-TypeB, QCL-TypeC, andQCL-TypeD.

A UE may receive an activation command that is used for mapping up to 8TCI states to the code points of DCI field ‘Transmission ConfigurationIndication’. If an HARQ-ACK corresponding to a PDSCH that carries theactivation command is transmitted from slot n, mapping between the codepoint of the DCI field ‘Transmission Configuration Indication’ and theTCI state may be applied after a predetermined time period is passed(for example, from slot n+3 N^(subframe,μ) _(slot)+1). After receivingan initial higher layer configuration of the TCI state and beforereceiving the activation command, the UE may assume that DM-RS ports ofa PDSCH of a serving cell are at a quasi co-location with an SS/PBCHblock determined from the initial access procedure for ‘QCL-TypeA’. Ifapplicable, the operation above may be the same for ‘QCL-TypeD’.

Option 4) Priority Due to Time Order of Monitoring Occasions

A UE may apply an Rx beam associated with a first encountered searchspace set according to a search space set monitoring order of eachCORESET. In other words, priority of each CORESET may be determinedaccording to a start symbol index of the CORESET. If the same CORESET isassociated to a plurality of search space sets and has the same startsymbol, an Rx beam may be determined based on the priority such as asearch space set index.

In other words, as the start symbol index of an associated CORESET amongsearch space sets that have to be monitored becomes lower (or higher),the associated CORESET may have high priority.

Option 5) Priority of a CORESET may be determined according to thenumber of search space sets associated with the CORESET.

As described above, in NR, 3 CORESETs and 10 search space sets may beconfigured for each BWP, which indicates that a plurality of searchspace sets may be associated with one CORESET. Option 5 is related to atechnique for allocating high priority to a CORESET with which a largenumber of search space sets are associated under a condition where aplurality of search space sets associated with a plurality of CORESETshave to be monitored in a specific slot, and TCI state of each CORESETis different from each other. At this time, the number of associatedsearch space sets may be limited to the search space sets that performmonitoring in the corresponding slot.

Option 6) Priority of a CORESET May be Determined Based on TCI State.

In other words, priority may be determined by the TCI state set to eachCORESET. As one example, among TCI states set by an RRC signal, the TCIstate with a lower (or higher) index may be set to have higher priority.Or to apply the most recent information of a channel status, the TCIstate that has most recently been configured in time order may be set tohave the highest priority. A gNB may inform of part of TCI states (forexample, 8) among a plurality of predetermined TCI states (for example,64) through an RRC message and inform of one from among the part of TCIstates through a MAC CE. Or, the gNB may directly inform of one fromamong a plurality of predetermined TCI states through an RRC message.

In another technique, priority may be determined according to atechnique for determining the TCI state of each CORESET, which may beregarded as a technique that puts high priority to the TCI state inwhich channel change may be quickly dealt with. For example, a CORESETfor which the TCI state is chosen through MAC CE signaling from among aplurality of TCI states indicated by an RRC signal for a specificCORESET may have higher priority than a CORESET for which the TCI stateis configured only through RRC signaling.

In addition, when a priority rule is determined as described above, aCORESET with low priority may have reduced monitoring occasions in a waythat monitoring is not performed in a slot where overlap is occurred ormay experience performance degradation with an increased frequency.Therefore, the present disclosure additionally describes changing thepriority rule periodically or non-periodically. This change may beperformed in a predefined manner or by an indication of the network. Forexample, a slot (subframe or frame) index may be used as a criterion forchanging the priority rule. As one example, if the option 2) is applied,and the slot index is an odd number, high priority is set to the CORESETassociated with a search space set with a low index while, if the slotindex is an even number, high priority may be set to the CORESETassociated with a search space set with a high index. Then an advantagemay be obtained that monitoring occasions for a specific CORESET or aspecific search space set are prevented from being reduced due topriority.

The descriptions above describe a technique for selecting which TCIstate to configure an Rx beam when CORESETs having different TCI stateson a specific time resource are configured the same. When a CORESET hasboth of the time resource overlapping a different CORESET and the timeresource existing only in the corresponding CORESET, the presentdisclosure additionally describes a technique for configuring an Rx beamwith respect to each region.

FIG. 13 illustrates an example of a case where two different CORESETsconfigured with different TCI states overlap each other in the timedomain.

As shown in FIG. 13, when monitoring is performed on each CORESET, a UEapplies different Rx beams, and when two CORESETs are overlapped, an Rxbeam that has to be applied by the UE (or TCI state that has to beassumed by the UE) may be determined according to the described priorityrule.

For example, if the priority of CORESET #2 of FIG. 13 is high, a UE mayapply Rx beam #1 in the overlapped region. However, in this case, whichRx beam to use for reception has to be determined at symbol #2 ofCORESET #3. To this purpose, the present disclosure describes thefollowing options, which may be implemented separately or in the form ofa combination thereof. To configure an Rx beam of a specific CORESET mayindicate to configure an Rx beam suitable for the TCI state of thecorresponding CORESET.

In addition, the following options may be performed for each set of aCORESET for each slot. For example, each set may be composed of CORESETsoverlapped partly or completely with each other in the time domain, andall of the CORESETs existing within one slot may comprise one set.

Option 1) Configuration of Rx Beam According to Priority for Each TimeResource

Based on the TCI state of a CORESET with the highest priority at eachtime resource (for example, OFDM symbol), an Rx beam at thecorresponding time resource may be configured. In this case, there aretimes that the same precoding may not be assumed for neighboring symbolsdue to different Rx beams within the same CORESET, and it may be assumedthat time domain REG bundling is not applied in the correspondingCORESET. Or it may be assumed that time domain bundling is applied onlywithin a time resource that uses the same Rx beam.

Option 2) It is related to a technique for applying an Rx beam withrespect to a CORESET with the highest priority among overlappingCORESETs to a plurality of CORESETs including the overlapped region.

With respect to the CORESETs including the same time resource, option 2may configure an Rx beam for the entire overlapping CORESETs based onthe TCI state of a CORESET with the highest priority among thecorresponding CORESETs. It may indicate that CORESETs not overlapped inthe time domain (for example, at symbol level) may configure an Rx beambased on the TCI state of each CORESET.

Option 3) When a plurality of CORESETs having different TCI states inone slot exist, the TCI state of a CORESET determined to have thehighest priority according to the described priority rule may be appliedto the whole of the corresponding slots. It may indicate that whendifferent CORESETs configured with different TCI states are monitored inthe same slot, a CORESET with low priority may change an Rx beam onlyfor the case of the corresponding slot (namely by assuming a TCI statedifferent from the configuration).

Option 4) It may be assumed that a UE performs monitoring only forcandidates of search space sets belonging to a CORESET with the highestpriority when CORESETs configured with different TCI states areoverlapped partly or completely in the time domain. Also, it mayindicate that monitoring of CORESETs not overlapped in the time domainmay have to be performed according to the configuration. Or it may beinterpreted that when CORESETs that have to assume different Rx beams inthe corresponding slot are overlapped, monitoring is performed only fora CORESET with the highest priority over the whole of the correspondingslot.

When a BFR CORESET/search space set has to be monitored, and the TCIstate at the corresponding BFR CORESET is different from an existingCORESET (namely a CORESET/search space set configured to performmonitoring before BFR), the option 4 may include a case where thecorresponding slot performs monitoring of only the BFR CORESET. Also,the option may include a case where existing CORESETs and BFR CORESETare monitored in the same slot, and when a particular CORESET among theexisting CORESETs uses the same Rx beam as the BFR CORESET, monitoringof the corresponding CORESET is performed.

For example, a UE may select a first CORESET including a search spacewith the lowest index (or ID) at the monitoring occasion of an active DLBWP of a serving cell with the lowest serving cell index. At this time,overlapping search spaces associated with other CORESETs having the sameQCL-TypeD properties as the first CORESET may also be monitored, whicheventually indicates that in the existence of CORESETs using the same Rxbeam as the first CORESET, PDCCH monitoring is also performed for theCORESETs.

<QCL Assumption for CORESET without TCI-State PDCCH>

Information Element (IE) called “ControlResourceSet” may be provided foreach CORESET. And to provide a QCL relationship between a CORESET and DLRS/SSB, a parameter called “tci-StatesPDCCH” may be configured withinthe IE.

However, since the “tci-StatesPDCCH” is an optional parameter, theparameter may not be configured for part of a plurality of CORESETs.Such a CORESET may be referred to as a TCI-less CORESET, and a defaultQCL assumption is needed to determine an Rx beam for receiving a PDCCHin a TCI-less CORESET.

With respect to a TCI-less CORESET, a UE may assume QCL from a CORESETfor which the most recent RACH process has been applied as the defaultQCL.

With respect to a BFR-CORESET (for a beam failure recovery process), aUE may assume that a DL RS of a candidate beam identified by the UE uponrequest of beam failure recovery and the dedicated CORESET are spatiallyQCLed.

In terms of PDCCH, for a BFR-CORESET, it may indicate that implicitspatial QCL update (irrespective of CORESET configuration) through beamfailure recovery and/or beam management process is assumed.

Besides the BFR-CORESET, it is necessary to clarify which CORESET is notassociated with TCI states. For example, CORESET #0 (by PBCH) andCORESET #1 (by RMSI) may not be associated with TCI states. In general,it is preferable that TCI states are configured in the case of otherCORESETs for USS operations.

In some scenarios, it may also be necessary to clarify whether a RACHprocess may include free-contention. Free-contention may be implementedbased on a CSI-RS without involving an SSB, and QCL associated with theCSI-RS may not be reliable for CORESET #0 and/or CORESET #1. Therefore,it may be safer to change QCL information based on the recentcontention-based RACH process at least for the CORESET #0 and theCORESET #1.

In other words, a QCL assumption derived from the most recentlyperformed RACH process may be applied to the CORESET for which‘tci-StatesPDCCH’ has not been configured.

In what follows, more specifically, a technique for deriving a QCLassumption is described additionally. In what follows, contention-basedRACH may indicate that a RACH process at a resource associated with thebest SSB (from a measurement result) is performed based on SSBs. Acontention-free RACH process may indicate a case where a RACH process isperformed at a resource associated with a CSI-RS port (or SSB) bysignaling of a gNB.

Since a contention-free RACH process is based on a networkconfiguration, signaling may be performed irrespective of measurement,or the network may perform signaling based on a measurement report of aUE. Also, in the case of a CSI-RS port, association with an SSB may ormay not be signaled. In other words, a contention-free RACH process maynot be able to confirm association with an SSB and reflection of ameasurement result. This may act as a factor that degrades, inconjunction with an SSB, performance of the operation of a CORESET andCORESET #0 and #1 for which a search space set may be configured. Forexample, there are times that a UE configures an Rx beam based on theassumption of an erroneous transmission beam.

1. A UE may apply a QCL assumption derived from the most recentlyperformed RACH process to a TCI-less CORESET irrespective of the type(namely contention-based/contention-free RACH process) of RACH process.

2. A UE may apply the QCL assumption of a TCI-less CORESET only to theresult derived from the most recently performed contention-based RACHprocess. For example, if the most recently performed RACH process is infact contention-free, the UE may ignore the corresponding result andapply the QCL assumption derived from the most recently performedcontention-based RACH process to the corresponding CORESET.

3. For each CORESET, a QCL assumption of a different RACH process may beused. For example, CORESET #0 (and/or #1) may apply the QCL assumptionderived from the most recently performed contention-based RACH processwhile the remaining CORESETs may derive a QCL assumption from the mostrecently performed RACH process irrespective of contention.

As another example, a CORESET for which a CSS is configured may apply aQCL assumption derived from the most recently performed contention-basedRACH process while a CORESET for which a USS is configured may derive aQCL assumption from the most recently performed RACH processirrespective of contention. At this time, a QCL assumption may beapplied, which is derived from the most recently performedcontention-based RACH process of a CORESET for which both of the CSS andUSS are configured.

4. Even though the described techniques are based on a contention-freeRACH process, if an associated SSB is indicated, or an implicitlyassociated SSB is known, a QCL assumption derived from the correspondingcontention-free RACH process may be applied to a TCI-less CORESET.

In addition, according to the present disclosure, through higher layersignaling, the network may inform a UE of from which RACH process type aQCL assumption is derived with respect to a TCI-less CORESET. At thistime, a technique for informing a UE of the SSB information associatedwith a CSI-RS port given during a contention-free RACH process may alsobe included.

<QCL Assumption Between Overlapped CORESETs in Time Domain>

Each CORESET may have its own QCL assumption. And different CORESETs maybe overlapped in the time domain and/or frequency domain. This mayindicate that CORESETs having different QCL assumptions may beoverlapped in the same symbol.

A UE determines an Rx beam for monitoring each CORESET by taking intoaccount the TCI state of the CORESET. Therefore, if CORESETs havingdifferent QCL assumptions are overlapped at a resource in the timedomain (for example, OFDM symbol), the UE may have to support aplurality of Rx beams or have to select one Rx beam (or TCI state)according to a specific selection rule. Until now, UEs that use aplurality of Rx beams are not considered. Therefore, the followingoptions may be considered.

Option 1) Skip Monitoring of a CORESET with Low Priority

A CORESET selection rule may be applied when CORESETs having different(spatial) QCLs are overlapped at a time resource. And a UE may skipmonitoring candidates included in an unselected CORESET. Priority ofeach CORESET may be determined according to, for example, CORESET ID,the number of search space sets associated with the CORESET, andassociated search space type. Search space type may be divided intoCommon Search Space (CSS) and UE-specific Search Space (USS). Amonitoring occasion for a PDCCH may be configured by a combination of aCORESET and a search space set associated with the CORESET. For example,a CSS may be associated with a first CORESET, and an USS may beassociated with a second CORESET; and when the first and the secondCORESETs are overlapped in the time domain, a UE may monitor only thefirst CORESET.

Option 2) Representative Spatial QCL for Overlapped CORESETs

Option 2 may arrange overlapped CORESETs according to the priority ruleof the option 1 and change the QCL state in a CORESET with low priorityinstead of deleting the CORESET with low priority. In other words, foroverlapped CORESETs, the same spatial QCL is assumed, and by using theCORESET priority mentioned in the option 1, a representative QCL may beselected. In other words, the QCL assumption for overlapped CORESETs mayfollow the QCL of a CORESET with the highest priority. Although thisoption may provide more PDCCH transmission and reception occasions,PDCCH performance of a CORESET with low priority may be decreased due toinconsistency between a transmission beam and an Rx beam.

Option 3) Technique that does not Allow Overlap of CORESETs HavingDifferent Spatial QCLs

A UE may assume that the network does not schedule overlapped CORESETshaving different spatial QCLs. However, it is not certain that overlapmay always be avoided through scheduling.

<Candidate Mapping for Case 2 where Monitoring Occasions for the SameSearch Space of the Same CORESET in One Slot are Configured MultipleTimes>

The number of CCEs for channel estimation for each slot of case 2 may bethe same as case 1. The case 1 describes a situation where only onemonitoring occasion may be configured in one slot. In other words, forboth of the case 1 and 2, the number of CCEs for channel estimation foreach slot may be {56, 56, 48, 32} in a sequential order with respect tothe subcarrier spacing (SCS) {15 kHz, 30 kHz, 60 kHz, 120 kHz}.

The case 1 or case 2 may be configured for a UE. A UE may be configuredto monitor search space sets with respect to the case 1 and 2. Forexample, common information may be transmitted through resources(slot-based scheduling) shared between eMBB and URLLC. Andservice-specific data may be transmitted by slot-based scheduling foreMBB and transmitted by non-slot based scheduling for URLLC. In thiscase, URLLC UEs may receive two types (namely case 1 and case 2).

Proposal 1: A UE may be configured to monitor both of the case 1 searchspace set and case 2 search space set, and the search space sets may bemonitored within one slot.

Proposal 2: The maximum number of CCEs for channel estimation for eachslot, for each UE, and for each component carrier may be {56, 56, 48,32} in a sequential manner with respect to sub-carrier spacing {15 kHz,30 kHz, 60 kHz, 120 kHz} irrespective of CORESET/SS configuration. Thismay be applied the same for a BD limit.

<Candidate Mapping in Case 2>

If the number of BDs/CCEs configured in the SS set configuration isalmost the same between the case 1 and 2, the number of requiredBDs/CCEs of the case 2 is normally much larger than that of the case 1.From the viewpoint of counting the number of CCEs with respect to asearch space set of the case 2, the number of CCEs required for eachmonitoring occasion has to be multiplied by the number of monitoringoccasions within one slot. Therefore, when search space set levelchannel estimation/BD processing is used together for the case 2, thetotal number of monitoring occasions of the case 2 may be reducedparticularly when a large number of monitoring occasions are given. Torelieve such an effect, monitoring occasion-based candidate selectionmay be additionally taken into account (for example, part of monitoringoccasions may be dropped).

Proposal 1: Search space set-level PDCCH mapping within a slot may alsobe used for BD/CE complexity processing with respect to the case 2.

<BFR CORESET/Search Space Set>

A BFR CORESET and its associated search space set may be formed for thebeam failure recovery procedure. The BFR CORESET/search space set isactivated by the beam failure recovery procedure, and a UE may notexpect PDCCH candidate monitoring in the BFR CORESET before the beamfailure recovery procedure (for example, PRACH transmission) and afterconfiguration of a new CORESET/search space set or update of TCI.

Meanwhile, it is not certain whether PDCCH monitoring is performed in anexisting CORESET (namely a CORESET configured to be monitored before theBFR procedure) in a monitoring window of the BFR CORESET. Since commoninformation (for example, SFI, system information, and paging) may notbe monitored in the BFR CORESET, it is preferable that a UE may monitora PDCCH candidate of the existing CORESET even in the BFR CORESETmonitoring window.

Proposal 2: A UE may continue monitoring in an active CORESET other thana BFR CORESET during the BFR process.

The TCI state of a CORESET may be expected to be updated only through anexplicit configuration. Therefore, during the BFR process, a UE maymonitor a CORESET in an old TCI state. When a BFR CORESET and otherCORESETs are monitored at the same time resource together withpotentially different QCL/TCI information (therefore, when a potentiallydifferent Rx beam is derived), a processing technique therefor isneeded. A simple solution is that a UE skips the old CORESET monitoringwhen a BFR CORESET overlaps an old CORESET in the time domain. In otherwords, when other CORESETs and the BFR CORESET collide with each other,the BFR CORESET is prioritized.

Another problem is related to whether a UE have to count (include) aCCE/BD with respect to a BFR-search space under a channel estimation/BDlimit. Some implementations of the present disclosure count (include) aCCE/BD of the BFR-search space at the time of monitoring.

It has been assumed that a CSS has higher priority than an USS in thePDCCH mapping, and the numbers of BDs/CCEs of a CSS do not exceed therespective limits. However, in a slot configured to monitor the BFRCORESET, the number of BDs/CCEs of the BFR CORESET may have to beregarded as a PDCCH mapping rule. The BFR CORESET/search space set mayhave the highest priority among the PDCCH mapping rules, and an existingPDCCH mapping rule may be applied to other search space sets. Thenunless a sum of CCEs of the CSS and BFR-search space is guaranteed notto exceed a limit of a UE, the CSS may have to be deleted when theBFR-search space is monitored. In order not to cause too muchconfiguration flexibility, the CSS may be dropped based on a searchspace set index when the BFR-search space is monitored.

Proposal 3: If a BFR CORESET overlaps other CORESET in the time domain,and at least QCL information is different between the BFR CORESET andthe other CORESET, a UE doesn't have to monitor the other CORESET for aPDCCH candidate.

Proposal 4: When a BFR CORESET/search space set is monitored, it mayhave the highest priority (irrespective of the search space type) withrespect to the PDCCH candidate mapping rule. A CSS associated with otherCORESET may be dropped according to a search space set index while theBFR search space is being monitored.

In the descriptions above, it has been described that when a pluralityof CORESETs configured with different TCI states are overlapped partlyor completely in the time domain, the TCI state in the overlapped regionis assumed according to the priorities of the CORESETs. Additionally,the present disclosure describes a technique for applying the priorityrule described above. The techniques described below may be applied tothe options that do not perform monitoring for CORESETs with lowpriority among the options described above.

<TCI Assumption Among Overlapped CORESETs>

Technique 1) TCI Assumption Due to Reporting of UE

FIG. 14 illustrates an example of an operation technique between a gNBand a UE according to one implementation of the present disclosure.

Referring to FIG. 14, a gNB (or network) may transmit a specificparameter, for example, a parameter called “groupBasedBeamReporting” toa UE S141. By using the parameter, the gNB may configure whether the UEreports a beam group that may be received simultaneously.

For example, when a UE is configured with ‘CSI-REportConfig’ for which ahigher layer parameter ‘reportQuantity’ is configured with ‘cri-RSRP’ or‘SSB-Index-RSRP’,

1) If the parameter ‘groupBasedBeamReporting’ is set to ‘disabled’, theUE is not requested to update measurement of resources larger than 64resources (CSI-RS or SSB), but for each report configuration, the UE mayhave to report a different CSI-RS resource indicator (CRI) or SSBresource indicator (SSBRI) via a single report ‘nrofReportedRS’.

2) If the parameter ‘groupBasedBeamReporting’ is set to ‘enabled’, theUE is not requested to update measurement of resources larger than 64resources (CSI-RS or SSB), but for each report configuration, the UE mayhave to report two different CRIs or SSBRIs via a single report occasion(time). Here, the UE may receive the CSI-RS and/or SSB resourcessimultaneously by using a single space region reception filter (RX beam)or by using multiple space region reception filters.

If the higher layer parameter ‘groupBasedBeamReporting’ is set to‘enabled’, the UE may report TCI states (CRI or SSBRI) that may bereceived simultaneously S142. For example, the UE may report twodifferent CRIs or SSBRIs in one report. This indicates that the UE mayreceive two reported TCI states related to the CSI-RS or SSBsimultaneously. In this case, whether the UE receives the TCI states byusing the same Rx beam or different Rx beams may not be indicated. Thisindicates that there are times that the UE receives the TCI statessimultaneously even though the TCI states are different from each other,and the UE report the corresponding information to the network.

Based on the report, the gNB and the UE may determine whether to applythe priority rule for overlapped CORESETs S143.

For example, when a plurality of TCI states, which have been reported asbeing possible to be received by the UE, are set to the same symbol, theaforementioned priority rule may not be applied. In other words, whenthe CORESETs having different TCI states are overlapped in the timedomain, if the TCI states of the CORESETs may be received simultaneouslyby the UE, control channel monitoring may be performed for all of theCORESETs without applying the aforementioned priority rule. On the otherhand, when TCI states of overlapped CORESETs may not be receivedsimultaneously, the priority rule described above may be applied. Inother words, it may indicate that if CORESETs with different TCI statesare overlapped in the time domain (symbol), whether to apply thepriority rule for CORESETs or TCI states at the overlapped symbol may bedetermined based on a (beam group) report of the UE.

Even through TCI states of overlapped CORESETs are configureddifferently, and the UE is able to receive the corresponding TCI statesby using the same Rx beam, if a combination of the corresponding TCIstates does not coincide with a beam group that the UE has reported(namely in the case of an unreported combination), the TCI state of anoverlapped region may be assumed according to the described priorityrule. This indicates that the priority rule described above may beapplied based on an Rx beam of the UE (which is commonly recognized bythe network and the UE).

Technique 2) TCI Assumption Based on Signaling of Network

The description above describes determining whether to apply a priorityrule to overlapped CORESETs based on reporting of a UE. As anothertechnique, the present disclosure describes determining whether to applythe aforementioned priority rule based on signaling of the network.

In NR, the network may signal the QCL relationship between a TrackingReference Signal (TRS), CSI-RS (for BM, CSI, or tracking), and SSB byusing a higher layer signal such as an RRC signal. The QCL types definedin NR are as follows. The QCL types have already been described withreference to Table 4.

1) ‘QCL-TypeA’: {Doppler shift, Doppler spread, average delay, delayspread}, 2) ‘QCL-TypeB’: {Doppler shift, Doppler spread}, 3)‘QCL-TypeC’: {average delay, Doppler shift}, 4) ‘QCL-TypeD’: {Spatialreception parameter}

The network may indicate the QCL relationship among different RSs byusing the technique described below. In the example of Table 6, below, anotation such as ‘A→B’ may indicate that A and B assume type D QCL, andA acts as a reference of B.

TABLE 6 QCL linkage for above 6 GHz Signalling SSB -> TRS w.r.t averagedelay, Doppler QCL type: C + D shift, spatial reception parameters TRS-> CSI-RS for BM(beam management) QCL type: A + D w.r.t. average delay,Doppler shift, delay spread, Doppler spread estimation TRS -> CSI-RS forCSI w.r.t. average QCL type: A delay, Doppler shift, delay spread,Doppler spread estimation TRS -> DMRS for PDCCH w.r.t. QCL type: A + Daverage delay, Doppler shift, delay spread, Doppler spread estimationTRS -> DMRS for PDSCH w.r.t. QCL type: A + D average delay, Dopplershift, delay spread, Doppler spread estimation SSB -> CSI-RS for BMw.r.t. QCL type: C + D average delay, Doppler shift, spatial receptionparameters SSB -> CSI-RS for CSI w.r.t, QCL type: D spatial receptionparameters SSB -> DMRS for PDCCH (before QCL type: A + D TRS isconfigured) w.r.t. average delay, Doppler shift, delay spread, Dopplerspread, spatial reception parameters SSB -> DMRS for PDSCH (before TRSQCL type: A + D is configured) w.r.t. average delay, Doppler shift,delay spread, Doppler spread, spatial reception parameters CSI-RS for BM-> DMRS for PDCCH QCL type: D w.r.t. spatial reception parameters CSI-RSfor BM -> DMRS for PDSCH QCL type: D w.r.t., spatial receptionparameters CSI-RS for CSI -> DMRS for PDSCH QCL type: A + D w.r.t.average delay, Doppler shift, delay spread, Doppler spread, spatialreception parameters (QCL parameters may not be derived directly fromCSI-RS for CSI) CSI-RS for BM -> CSI-RS for QCL type: D TRS/BM/CSIw.r.t. spatial reception parameters

As may be seen from Table 6, the network may inform the UE of the QCLassumption among RSs (for example, SSB, CSI-RS, TRS) that may be definedby TCI states through RRC signaling. As one example, the reference fortype D QCL with respect to a DMRS of a PDCCH may be given by SSB, TRS,and SCI-RS for beam management. Also, a QCL reference for CSI-RS may beincluded in the CSI-RS configuration; and SSB, TRS, CSI-RS, and so onmay be configured as the QCL reference.

The present disclosure describes applying a QCL combination, known to aUE through RRC signaling, also to a CORESET. In particular, the presentdisclosure describes determining whether to apply the priority ruledescribed above by using a QCL combination of the TCI state of a CORESETincluded in the corresponding CORESET configuration and the TCI stateknown through RRC signaling.

For example, when the TCI states of different CORESETs overlapped in thetime domain are SSB #2 and CSI-RS #8, respectively, if RRC signalingrelated to the QCL combination of the network indicates that the SSB #2and CSI-RS #8 assume type D QCL, the priority rule doesn't have to beapplied in the corresponding overlapped region, and the UE may performblind decoding for each CORESET. On the other hand, if a QCLrelationship among the corresponding TCI states is not configured forthe RRC signaling of the network, the UE may perform PDCCH mapping bywhich blind decoding is performed based on the described priority rule.

As another example, if TCI states of different CORESETs overlapped inthe time domain are configured to be CSI-RS #5 and CSI-RS #6,respectively; type D QCL reference of the CSI-RS #5 is SSB #4 in the RRCsignaling related to the QCL combination of the network; and the type DQCL reference of the CSI-RS #6 is the same as SSB #4, monitoring of eachCORESET may be performed without applying the priority rule to thecorresponding overlapped region (for example, without performingmonitoring skip for a CORESET with lower priority). The UE may derive atype D QCL relationship among TCI states configured for individualCORESETs based on the report of the UE and/or QCL-related signaling ofthe network.

FIG. 15 illustrates an example of a technique for control channelmonitoring of a UE according to the present disclosure.

Referring to FIG. 15, if physical downlink control channel (PDCCH)monitoring occasions are overlapped in a plurality of control resourcesets (CORESETs), the UE selects at least one CORESET from among theplurality of CORESETs S151.

The UE monitors a PDCCH only in the at least one selected CORESET, andin particular, if a first CORESET is selected as the at least oneCORESET, and if a first reference signal of the first CORESET isassociated with the same Synchronization Signal/PBCH Block (SSB) as asecond reference signal of a second CORESET, then the UE monitors thePDCCH in both the first CORESET and the second CORESET S152.

In some implementation, the UE may assume (for the purpose ofdetermining a CORESET) that the first CORESET and the second CORESEThave the same Quasi Co Location (QCL) properties (for example, QCL-TypeDproperties). As described above, the QCL-TypeD properties may be relatedto a spatial receive (Rx) parameter.

In some implementations, the technique of FIG. 15 may be used incombination with the technique of FIG. 12. For example, in selecting theat least one CORESET, a CORESET may be selected by assuming that apriority of a CORESET including a Common Search Space (CSS) is higherthan a priority of a CORESET including a UE-specific Search Space (USS).

Also, in some implementations, in selecting the at least one CORESET, ifthere exist multiple CORESETs including a CSS, then the UE may select aCORESET, from among the multiple CORESETs including the CSS, that has alowest index.

Also, in some implementations, among the plurality of CORESETs, aCORESET corresponding to a CSS with the lowest index may be selectedfrom a cell that has a lowest cell index and that includes the CSS.

FIG. 16 illustrates an example of two reference signals associated withthe same SSB described with reference to FIG. 15.

Referring to FIG. 16, a first CSI-RS located in a first CORESET 161 of afirst cell and a second CSI-RS located in a second CORESET of a secondcell may be associated with the same SSB. In this case, the two CSI-RSsmay be assumed to have the same QCL-TypeD properties.

Regarding the purpose of determining a CORESET, an SS/PBCH block may beregarded as having different QCL-TypeD properties from the CSI-RS.Regarding the purpose of determining a CORESET, the first CSI-RSassociated with an SS/PBCH block of the first cell and the second CSI-RSof the second cell associated with the SS/PBCH block may be considered(assumed) to have the same QCL-TypeD properties. If PDCCH monitoringoccasions are overlapped in a plurality of CORESETs, the UE may select aspecific CORESET (for example, a CORESET corresponding to a CSS set withthe lowest index in a cell with the lowest index containing a CSS) andmonitor a PDCCH only in the specific CORESET. At this time, if adifferent CORESET has the same QCL-TypeD properties as the specificCORESET, a PDCCH is monitored also in the different CORESET. Forexample, if the specific CORESET is the first CORESET, the differentCORESET may be the second CORESET.

<Overlap Handling and Complexity Handling>

The present disclosure has described a priority rule and PDCCH mappingrule for a case when CORESETs with different TCI states are overlappedin the time domain. In NR, a priority rule and a PDCCH mapping rulebased on blind detection and channel estimation complexity areadditionally defined, and when blind decoding and channel estimationthat exceed a predefined limit in a specific slot are configured, atechnique for mapping a PDCCH according to the priority rule is defined.

The present disclosure describes a PDCCH mapping rule for overlaphandling and an order of applying the PDCCH mapping rule for complexityhandling.

If complexity handling is performed first before the overlap handling,the number of candidates set according to the blind decoding(BD)/channel estimation (CE) capability may be additionally reduced;therefore, UE capability may be wasted. Therefore, the presentdisclosure describes usually performing the PDCCH mapping rule foroverlap handling first before the PDCCH mapping rule for complexityhandling.

In some scenarios, it may be preferable to reduce the number ofcandidates as much as possible for the purpose of power saving.Therefore, the present disclosure additionally describes determining thePDCCH mapping rule to be performed first by the network (or implicitly).As one example, suppose the network indicates information about whichPDCCH mapping rule is to be applied first through higher layersignaling, or the time at which a UE transitions to a power saving modeis determined from the same understanding between the network and theUE. If the UE satisfies a condition for transitioning to the powersaving mode, the UE may first perform the PDCCH mapping rule forcomplexity handling and then perform the PDCCH mapping rule for overlaphandling.

FIG. 17 is a block diagram showing an example of components of atransmitting device 1810 and a receiving device 1820 for implementingthe present disclosure. Here, the transmitting device and the receivingdevice may be a base station and a terminal.

The transmitting device 1810 and the receiving device 1820 mayrespectively include transceivers 1812 and 1822 capable of transmittingor receiving radio frequency (RF) signals carrying information, data,signals and messages, and at least one memory, such as memories 1813 and1823, for storing various types of information regarding communicationin a wireless communication system. The transmitting device 1810 and thereceiving device 1820 may also each implement at least one processor,such as processors 1811 and 1821, that are connected to components suchas the transceivers 1812 and 1822 and the memories 1813 and 1823 andconfigured to control the memories 1813 and 1823 and/or the transceivers1812 and 1822 such that the corresponding devices perform at least oneof implementations of the present disclosure.

The memories 1813 and 1823 can store programs for processing and controlof the processors 1811 and 1821 and temporarily store input/outputinformation. The memories 1813 and 1823 may be used as buffers.

The processors 1811 and 1821 generally control overall operations ofvarious modules in the transmitting device and the receiving device.Particularly, the processors 1811 and 1821 can execute various controlfunctions for implementing the present disclosure. The processors 1811and 1821 may be referred to as controllers, microcontrollers,microprocessors, microcomputers, etc. The processors 1811 and 1821 canbe realized by hardware, firmware, software or a combination thereof.When the present disclosure is realized using hardware, the processors1811 and 1821 may include ASICs (application specific integratedcircuits), DSPs (digital signal processors), DSPDs (digital signalprocessing devices), PLDs (programmable logic devices), FPGAs (fieldprogrammable gate arrays) or the like configured to implement thepresent disclosure. When the present disclosure is realized usingfirmware or software, the firmware or software may be configured toinclude modules, procedures or functions for performing functions oroperations of the present disclosure, and the firmware or softwareconfigured to implement the present disclosure may be included in theprocessors 1811 and 1821 or stored in the memories 1813 and 1823 andexecuted by the processors 1811 and 1821.

The processor 1811 of the transmitting device 1810 can performpredetermined coding and modulation on a signal and/or data to betransmitted to the outside and then transmit the signal and/or data tothe transceiver 1812. For example, the processor 1811 can performdemultiplexing, channel coding, scrambling and modulation on a datastring to be transmitted to generate a codeword. The codeword caninclude information equivalent to a transport block which is a datablock provided by an MAC layer. One transport block (TB) can be codedinto one codeword. Each codeword can be transmitted to the receivingdevice through one or more layers. The transceiver 1812 may include anoscillator for frequency up-conversion. The transceiver 1812 may includeone or multiple transmission antennas.

The signal processing procedure of the receiving device 1820 may bereverse to the signal processing procedure of the transmitting device1810. The transceiver 1822 of the receiving device 1820 can receive RFsignals transmitted from the transmitting device 1810 under the controlof the processor 1821. The transceiver 1822 may include one or multiplereception antennas. The transceiver 1822 can frequency-down-convertsignals received through the reception antennas to restore basebandsignals. The transceiver 1822 may include an oscillator for frequencydown conversion. The processor 1821 can perform decoding anddemodulation on RF signals received through the reception antennas torestore data that is intended to be transmitted by the transmittingdevice 1810.

The transceivers 1812 and 1822 may include one or multiple antennas. Theantennas can transmit signals processed by the transceivers 1812 and1822 to the outside or receive RF signals from the outside and deliverthe RF signal to the transceivers 1812 and 1822 under the control of theprocessors 1811 and 1821 according to an implementation of the presentdisclosure. The antennas may be referred to as antenna ports. Eachantenna may correspond to one physical antenna or may be configured by acombination of a plurality of physical antenna elements. A signaltransmitted from each antenna cannot be decomposed by the receivingdevice 1820. A reference signal (RS) transmitted corresponding to anantenna defines an antenna from the viewpoint of the receiving device1820 and can allow the receiving device 1820 to be able to estimate achannel with respect to the antenna irrespective of whether the channelis a single radio channel from a physical antenna or a composite channelfrom a plurality of physical antenna elements including the antenna.That is, an antenna can be defined such that a channel carrying a symbolon the antenna can be derived from the channel over which another symbolon the same antenna is transmitted. A transceiver which supports amulti-input multi-output (MIMO) function of transmitting and receivingdata using a plurality of antennas may be connected to two or moreantennas.

FIG. 18 illustrates an example of a signal processing module structurein the transmitting device 1810. Here, signal processing can beperformed by at least one processor of a base station/terminal, such asthe processors 1811 and 1821 of FIG. 17.

Referring to FIG. 18, the transmitting device 1810 included in aterminal or a base station may include scramblers 301, modulators 302, alayer mapper 303, an antenna port mapper 304, resource block mappers 305and signal generators 306.

The transmitting device 1810 can transmit one or more codewords. Codedbits in each codeword are scrambled by the corresponding scrambler 301and transmitted over a physical channel. A codeword may be referred toas a data string and may be equivalent to a transport block which is adata block provided by the MAC layer.

Scrambled bits are modulated into complex-valued modulation symbols bythe corresponding modulator 302. The modulator 302 can modulate thescrambled bits according to a modulation scheme to arrangecomplex-valued modulation symbols representing positions on a signalconstellation. The modulation scheme is not limited and m-PSK (m-PhaseShift Keying) or m-QAM (m-Quadrature Amplitude Modulation) may be usedto modulate the coded data. The modulator may be referred to as amodulation mapper.

The complex-valued modulation symbols can be mapped to one or moretransport layers by the layer mapper 303. Complex-valued modulationsymbols on each layer can be mapped by the antenna port mapper 304 fortransmission on an antenna port.

Each resource block mapper 305 can map complex-valued modulation symbolswith respect to each antenna port to appropriate resource elements in avirtual resource block allocated for transmission. The resource blockmapper can map the virtual resource block to a physical resource blockaccording to an appropriate mapping scheme. The resource block mapper305 can allocate complex-valued modulation symbols with respect to eachantenna port to appropriate subcarriers and multiplex the complex-valuedmodulation symbols according to a user.

Each signal generator 306 can modulate complex-valued modulation symbolswith respect to each antenna port, that is, antenna-specific symbols,according to a specific modulation scheme, for example, OFDM (OrthogonalFrequency Division Multiplexing), to generate a complex-valued timedomain OFDM symbol signal. The signal generator can perform IFFT(Inverse Fast Fourier Transform) on the antenna-specific symbols, and aCP (cyclic Prefix) can be inserted into time domain symbols on whichIFFT has been performed. OFDM symbols are subjected to digital-analogconversion and frequency up-conversion and then transmitted to thereceiving device through each transmission antenna. The signal generatormay include an IFFT module, a CP inserting unit, a digital-to-analogconverter (DAC) and a frequency upconverter.

FIG. 19 illustrates another example of the signal processing modulestructure in the transmitting device 1810. Here, signal processing canbe performed by at least one processor of a terminal/base station, suchas the processors 1811 and 1821 of FIG. 17.

Referring to FIG. 19, the transmitting device 1810 included in aterminal or a base station may include scramblers 401, modulators 402, alayer mapper 403, a precoder 404, resource block mappers 405 and signalgenerators 406.

The transmitting device 1810 can scramble coded bits in a codeword bythe corresponding scrambler 401 and then transmit the scrambled codedbits through a physical channel.

Scrambled bits are modulated into complex-valued modulation symbols bythe corresponding modulator 402. The modulator can modulate thescrambled bits according to a predetermined modulation scheme to arrangecomplex-valued modulation symbols representing positions on a signalconstellation. The modulation scheme is not limited and pi/2-BPSK(pi/2-Binary Phase Shift Keying), m-PSK (m-Phase Shift Keying) or m-QAM(m-Quadrature Amplitude Modulation) may be used to modulate the codeddata.

The complex-valued modulation symbols can be mapped to one or moretransport layers by the layer mapper 403.

Complex-valued modulation symbols on each layer can be precoded by theprecoder 404 for transmission on an antenna port. Here, the precoder mayperform transform precoding on the complex-valued modulation symbols andthen perform precoding. Alternatively, the precoder may performprecoding without performing transform precoding. The precoder 404 canprocess the complex-valued modulation symbols according to MIMO usingmultiple transmission antennas to output antenna-specific symbols anddistribute the antenna-specific symbols to the corresponding resourceblock mapper 405. An output z of the precoder 404 can be obtained bymultiplying an output y of the layer mapper 403 by an N*M precodingmatrix W. Here, N is the number of antenna ports and M is the number oflayers.

Each resource block mapper 405 maps complex-valued modulation symbolswith respect to each antenna port to appropriate resource elements in avirtual resource block allocated for transmission.

The resource block mapper 405 can allocate complex-valued modulationsymbols to appropriate subcarriers and multiplex the complex-valuedmodulation symbols according to a user.

Each signal generator 406 can modulate complex-valued modulation symbolsaccording to a specific modulation scheme, for example, OFDM, togenerate a complex-valued time domain OFDM symbol signal. The signalgenerator 406 can perform IFFT (Inverse Fast Fourier Transform) onantenna-specific symbols, and a CP (cyclic Prefix) can be inserted intotime domain symbols on which IFFT has been performed. OFDM symbols aresubjected to digital-analog conversion and frequency up-conversion andthen transmitted to the receiving device through each transmissionantenna. The signal generator 406 may include an IFFT module, a CPinserting unit, a digital-to-analog converter (DAC) and a frequencyupconverter.

The signal processing procedure of the receiving device 1820 may bereverse to the signal processing procedure of the transmitting device.Specifically, the processor 1821 of the transmitting device 1810 decodesand demodulates RF signals received through antenna ports of thetransceiver 1822. The receiving device 1820 may include a plurality ofreception antennas, and signals received through the reception antennasare restored to baseband signals, and then multiplexed and demodulatedaccording to MIMO to be restored to a data string intended to betransmitted by the transmitting device 1810. The receiving device 1820may include a signal restoration unit for restoring received signals tobaseband signals, a multiplexer for combining and multiplexing receivedsignals, and a channel demodulator for demodulating multiplexed signalstrings into corresponding codewords. The signal restoration unit, themultiplexer and the channel demodulator may be configured as anintegrated module or independent modules for executing functionsthereof. More specifically, the signal restoration unit may include ananalog-to-digital converter (ADC) for converting an analog signal into adigital signal, a CP removal unit for removing a CP from the digitalsignal, an FET module for applying FFT (fast Fourier transform) to thesignal from which the CP has been removed to output frequency domainsymbols, and a resource element demapper/equalizer for restoring thefrequency domain symbols to antenna-specific symbols. Theantenna-specific symbols are restored to transport layers by themultiplexer and the transport layers are restored by the channeldemodulator to codewords intended to be transmitted by the transmittingdevice.

FIG. 20 illustrates an example of a wireless communication deviceaccording to an implementation example of the present disclosure.

Referring to FIG. 20, the wireless communication device, for example, aterminal may include, for example, at least one processor such asprocessor 2310, which may be a digital signal processor (DSP) or amicroprocessor, a transceiver 2335, a power management module 2305, anantenna 2340, a battery 2355, a display 2315, a keypad 2320, a globalpositioning system (GPS) chip 2360, a sensor 2365, at least one memorysuch as memory 2330, a subscriber identification module (SIM) card 2325,a speaker 2345 and a microphone 2350. A plurality of antennas and aplurality of processors may be provided.

The processor 2310 can implement functions, procedures and methodsdescribed in the present description. The processor 2310 in FIG. 20 maybe the processors 1811 and 1821 in FIG. 17.

The memory 2330 is connected to the processor 2310 and storesinformation related to operations of the processor. The memory may belocated inside or outside the processor and connected to the processorthrough various techniques such as wired connection and wirelessconnection. The memory 2330 in FIG. 20 may be the memories 1813 and 1823in FIG. 17.

A user can input various types of information such as telephone numbersusing various techniques such as pressing buttons of the keypad 2320 oractivating sound using the microphone 2350. The processor 2310 canreceive and process user information and execute an appropriate functionsuch as calling using an input telephone number. In some scenarios, datacan be retrieved from the SIM card 2325 or the memory 2330 to executeappropriate functions. In some scenarios, the processor 2310 can displayvarious types of information and data on the display 2315 for userconvenience.

The transceiver 2335 is connected to the processor 2310 and transmitand/or receive RF signals. The processor can control the transceiver inorder to start communication or to transmit RF signals including varioustypes of information or data such as voice communication data. Thetransceiver includes a transmitter and a receiver for transmitting andreceiving RF signals. The antenna 2340 can facilitate transmission andreception of RF signals. In some implementation examples, when thetransceiver receives an RF signal, the transceiver can forward andconvert the signal into a baseband frequency for processing performed bythe processor. The signal can be processed through various techniquessuch as converting into audible or readable information to be outputthrough the speaker 2345. The transceiver in FIG. 20 may be thetransceivers 1812 and 1822 in FIG. 17.

Although not shown in FIG. 20, various components such as a camera and auniversal serial bus (USB) port may be additionally included in theterminal. For example, the camera may be connected to the processor2310.

FIG. 20 is an example of implementation with respect to the terminal andimplementation examples of the present disclosure are not limitedthereto. The terminal need not essentially include all the componentsshown in FIG. 20. That is, some of the components, for example, thekeypad 2320, the GPS chip 2360, the sensor 2365 and the SIM card 2325may not be essential components. In this case, they may not be includedin the terminal.

FIG. 21 illustrates an example of a processor at the UE side.

The processor 2000 may include a monitoring occasion determination andresource selection module 2010 and a PDCCH monitoring module 2020. Theprocessor 2000 may correspond to the processor of FIGS. 17 to 20.

The monitoring occasion determination and resource selection module 2010may detect whether PDCCH monitoring occasions are overlapped in aplurality of CORESETs and if the PDCCH monitoring occasions areoverlapped, may select at least one CORESET among the plurality ofCORESETs.

The PDCCH monitoring module 2020 may monitor a PDCCH only in theselected at least one CORESET among the plurality of CORESETs.

FIG. 22 illustrates an example of a processor at the gNB side.

The processor 3000 may include a resource allocation module 3010 and aninformation transmission module 3020. The processor 3000 may correspondto the processor of FIGS. 17 to 20.

The resource allocation module 3010 may allocate a plurality of CORESETsto a UE. The information transmission module 3020 may transmit a PDCCHonly to a specific CORESET among the plurality of CORESETs.

What is claimed is:
 1. A method performed by a base station (BS) in awireless communication system, the method comprising: transmitting asynchronization signal/physical broadcast channel block (SSB);transmitting a first channel state information-reference signal (CSI-RS)for a first control resource set (CORESET); transmitting a second CSI-RSfor a second CORESET; and i) based on an overlap between physicaldownlink control channel (PDCCH) monitoring occasions of a userequipment (UE) in the first CORESET and the second CORESET and ii) basedon the first CSI-RS for the first CORESET and the second CSI-RS for thesecond CORESET being related with the SSB: transmitting a controlsignal, to be monitored in both the first CORESET and the second CORESETby the UE, through a PDCCH in at least one CORESET among the firstCORESET and the second CORESET.
 2. The method of claim 1, wherein thefirst CORESET includes a common search space (CSS) with a lowest indexamong multiple CORESETs that have overlapping PDCCH monitoringoccasions.
 3. The method of claim 1, wherein the first CORESET and thesecond CORESET are assumed to have same Quasi Co Location (QCL)properties.
 4. The method of claim 3, wherein the QCL properties arerelated to a spatial receive (Rx) parameter.
 5. A base station (BS), theBS comprising: a transceiver; at least one processor; and at least onecomputer memory operably connectable to the at least one processor andstoring instructions that, when executed by the at least one processor,perform operations comprising: transmitting a synchronizationsignal/physical broadcast channel block (SSB); transmitting a firstchannel state information-reference signal (CSI-RS) for a first controlresource set (CORESET); transmitting a second CSI-RS for a secondCORESET; and i) based on an overlap between physical downlink controlchannel (PDCCH) monitoring occasions of a user equipment (UE) in thefirst CORESET and the second CORESET and ii) based on the first CSI-RSfor the first CORESET and the second CSI-RS for the second CORESET beingrelated with the SSB: transmitting a control signal, to be monitored inboth the first CORESET and the second CORESET by the UE, through a PDCCHin at least one CORESET among the first CORESET and the second CORESET.6. The BS of claim 5, wherein the first CORESET includes a common searchspace (CSS) with a lowest index among multiple CORESETs that haveoverlapping PDCCH monitoring occasions.
 7. The BS of claim 5, whereinthe first CORESET and the second CORESET are assumed to have same QuasiCo Location (QCL) properties.
 8. The BS of claim 7, wherein the QCLproperties are related to a spatial receive (Rx) parameter.
 9. At leastone processor that is configured to control a wireless communicationdevice to perform operations comprising: transmitting a synchronizationsignal/physical broadcast channel block (SSB); transmitting a firstchannel state information-reference signal (CSI-RS) for a first controlresource set (CORESET); transmitting a second CSI-RS for a secondCORESET; and i) based on an overlap between physical downlink controlchannel (PDCCH) monitoring occasions of a user equipment (UE) in thefirst CORESET and the second CORESET and ii) based on the first CSI-RSfor the first CORESET and the second CSI-RS for the second CORESET beingrelated with the SSB: transmitting a control signal, to be monitored inboth the first CORESET and the second CORESET by the UE, through a PDCCHin at least one CORESET among the first CORESET and the second CORESET.